Add gamepad HID support following Linux 7.1 hid-input.c patterns:
Gamepad axes (GenericDesktop page 0x01):
- X (0x30), Y (0x31): stored in gamepad_axes[0..1]
(also still forwarded as mouse position for backward compat)
- Z (0x32), Rx (0x33), Ry (0x34), Rz (0x35):
stored in gamepad_axes[2..5] (triggers + right stick)
- Hat Switch (0x39): stored in hat_switch (i8)
Gamepad buttons (Button page 0x09):
- Extended from 3 to 32 buttons
- First 3 buttons still tracked as mouse buttons (backward compat)
- All button states tracked in gamepad_buttons (u32 bitmask)
State tracking:
- 6-axis array (gamepad_axes: [i32; 6])
- 32-button bitmask (gamepad_buttons: u32)
- D-pad hat switch (hat_switch: i8)
Cross-reference: Linux 7.1
- drivers/hid/hid-input.c: hidinput_configure_usage()
- map_abs(ABS_X|ABS_Y|ABS_Z|ABS_RX|ABS_RY|ABS_RZ|ABS_HAT0X)
- BTN_GAMEPAD / BTN_SOUTH / BTN_EAST / BTN_TR / BTN_TL
This means USB gamepads (Xbox, PlayStation, Switch Pro, generic HID)
will now produce axis and button events through ProducerHandle.
Add Caps Lock, Num Lock, and Scroll Lock LED synchronization
following Linux 7.1 hid-input.c: hidinput_output_event().
Led state tracking:
- Caps Lock (usage 0x39) → toggles bit 1
- Scroll Lock (usage 0x47) → toggles bit 2
- Num Lock (usage 0x53) → toggles bit 0
SET_REPORT (Output) via XhciClientHandle::device_request():
- PortReqTy::Class, PortReqRecipient::Interface
- bRequest = 0x09 (SET_REPORT)
- wValue = (0x02 << 8) | 0x00 (Output report type, report ID 0)
- wIndex = interface_num
- Data = 1-byte LED state
The SET_REPORT is sent only when the LED state changes (tracked
with last_led_state sentinel). A failed SET_REPORT is logged at
warn level but does not block the input loop.
Cross-reference: Linux 7.1
- drivers/hid/hid-input.c: hidinput_output_event()
- drivers/hid/usbhid/hid-core.c: usbhid_output_report()
- HID 1.11 spec §7.2.1: SET_REPORT request
This means USB keyboards with Caps/Num/Scroll Lock LEDs will now
have their LEDs synchronized with the host lock state.
First UAS (USB Attached SCSI) implementation slice, cross-referenced
with Linux 7.1 drivers/usb/storage/uas.c and uas-detect.h.
protocol/uas.rs (new, 253 lines):
- CommandIU (32 bytes), SenseIU (20 bytes), ResponseIU (20 bytes)
struct definitions matching the UAS specification
- UasTransport with 4 bulk pipes:
Pipe 1 = Command pipe (BULK OUT)
Pipe 2 = Status pipe (BULK IN)
Pipe 3 = Data-in pipe (BULK IN)
Pipe 4 = Data-out pipe (BULK OUT)
- uas_find_endpoint_pipes() heuristic: UAS interfaces always
have exactly 4 bulk endpoints in spec-mandated order
- UasTransport::init() opens all 4 endpoints via XhciEndpHandle
- Protocol trait implementation:
* send_command() builds CommandIU, writes to command pipe
* executes data phase on appropriate pipe
* reads ResponseIU or SenseIU from status pipe
* maps IU status to SendCommandStatus
- Streams deferred to P4 slice 2 (USB 2.0 sequential, no
CBW/CSW overhead)
protocol/mod.rs:
- mod uas promoted from //TODO stub to full module
- setup() now dispatches protocol 0x62 (USB_PR_UAS) to
UasTransport alongside 0x50 (BOT) to BulkOnlyTransport
Cross-reference: Linux 7.1
- drivers/usb/storage/uas.c: uas_configure_endpoints()
- drivers/usb/storage/uas-detect.h: uas_find_endpoints()
- drivers/usb/storage/uas.c: struct uas_dev_info pipe model
- include/uapi/linux/usb/ch11.h: USB_PR_UAS = 0x62
This means USB 3.0 storage devices supporting UAS will now use the
4-pipe IU protocol instead of falling back to BOT — a substantial
latency improvement even without streams.
Replace the polling-only main loop with interrupt-driven change
detection modeled on Linux 7.1 hub_irq().
Key changes:
1. Discover the hub's interrupt IN endpoint from the interface
descriptor (typically EP1 for USB 2.x, may be absent for USB 3).
Use EndpointTy::Interrupt + EndpDirection::In to match.
2. Open the endpoint via XhciClientHandle::open_endpoint(1) and
call transfer_read() to receive the status-change bitmap.
3. Build a per-port change mask from the bitmap:
Port N is bit (N-1) of byte (N-1)/8. Only ports whose bit is
set in the mask are polled for detailed GetPortStatus.
4. Graceful fallback: if the interrupt endpoint is absent or the
transfer fails, fall back to polling all ports at 200ms.
5. Interrupt-driven mode blocks on transfer_read() — no explicit
sleep needed. Polling mode sleeps 200ms per cycle (was 250ms,
tightened from 1000ms in P3 slice 1).
6. Added XhciEndpHandle import for endpoint operations.
Cross-reference: Linux 7.1
- drivers/usb/core/hub.c: hub_irq() — URB completion handler
- drivers/usb/core/hub.c: hub_configure() — interrupt endpoint setup
- include/linux/usb/ch11.h — hub status change bitmap format
This completes P3 hub maturity — power-on timing (slice 1) plus
interrupt-driven detection (slice 2) brings usbhubd to Linux 7.1
parity for the two most important hub operations.
First P3 hub-driver maturity improvements, cross-referenced with
Linux 7.1 drivers/usb/core/hub.c:
1. Power-on timing (hub_power_on + hub_power_on_good_delay)
- reads bPwrOn2PwrGood (V2: power_on_good; V3: default 10)
- sleeps power_on_good * 2ms after SET_FEATURE(PORT_POWER)
- minimum floor: 100ms (matches Linux hub_power_on_good_delay)
- logs the computed delay at startup
2. USB 3 hub stall fix
- ConfigureEndpointsReq no longer passes interface_desc or
alternate_setting for USB 3 hubs
- xHCI handles default-alt-0 derivation internally
- resolves the two TODOs that documented the stall symptom
3. SET_HUB_DEPTH with hub_depth() value
- previously passed port_id.hub_depth().into() which was
incorrect (returned route-string-derived depth)
- now logs the depth value explicitly
4. Polling interval tightened 1s -> 250ms
- interrupt-driven detection remains a follow-up (P3 slice 2)
- 250ms is a reasonable intermediate step for USB keyboard
responsiveness
5. wHubDelay recorded from V3 descriptor
- extracted from hub_desc.delay field
- displayed at startup; future P3 slices will accumulate
through the hub tree per Linux hub_configure()
Cross-reference: Linux 7.1
- drivers/usb/core/hub.c: hub_power_on()
- drivers/usb/core/hub.c: hub_power_on_good_delay()
- drivers/usb/core/hub.c: hub_activate()
- include/linux/usb/ch11.h: HUB_SET_DEPTH = 0x0C
Completes the TT-clear recovery path started in slice 2. Instead of
just logging the parent-hub metadata, we now issue the real
CLEAR_TT_BUFFER hub-class control request to flush stale TT state.
clear_tt_buffer_once()
- accepts child PortId and endpoint number
- reads parent_hub_slot_id, parent_port_num, parent_port_id
from persisted PortState
- builds devinfo field exactly as Linux 7.1 does:
(ep_number) | (dev_addr << 4) | (BULK << 11) | (IN << 15)
- uses TT port from parent_port_num (1-indexed)
- sends class-request CLEAR_TT_BUFFER via one-shot EP0 helper
- propagates errors as warnings; endpoint reset continues anyway
Call site (hard-reset recovery for Babble/DataBuffer/Trb/Split):
- TT-clear runs BEFORE endpoint reset per Linux 7.1 finish_td()
ordering
- only triggers when behind_highspeed_hub is true
- uses the stored parent_port_id directly (no CHashMap scan)
PortState gains parent_port_id: Option<PortId>
- persisted alongside parent_hub_slot_id and parent_port_num
- avoids scanning port_states at TT-clear time (CHashMap has
no iterator)
Cross-reference: Linux 7.1
- drivers/usb/core/hub.c: usb_hub_clear_tt_buffer()
- drivers/usb/host/xhci-ring.c: xhci_clear_hub_tt_buffer()
- driver_interface.rs: PortId definition
This completes the first implementation of P2-C error recovery:
- UsbTransaction: bounded soft retry (3x)
- Resource: bounded retry/backoff
- Stall: reset/restart + non-recursive device-side clear-halt
- Babble/DataBuffer/Trb/SplitTransaction: TT-clear (if behind HS hub)
+ hard endpoint reset
Implements the next recovery slice after the first active P2-C pass:
1. Persist parent-hub / TT metadata in PortState
- parent_hub_slot_id: Option<u8>
- parent_port_num: Option<u8>
- behind_highspeed_hub: bool
These are derived at attach time from PortId::parent() plus the
parent port's protocol_speed, matching the Linux 7.1 TT decision
rule: LS/FS device behind HS hub.
2. Add execute_control_transfer_once()
- single-attempt EP0 control transfer helper
- bypasses the recovery loop entirely
- used for device-side CLEAR_FEATURE(ENDPOINT_HALT)
3. Add clear_endpoint_halt_no_recovery()
- fetches bEndpointAddress from EndpDesc
- issues endpoint-recipient CLEAR_FEATURE(ENDPOINT_HALT)
with index = endpoint_address
- no recursive re-entry into maybe_recover_transfer_error
4. Wire the helper into Stall recovery for non-control endpoints
- host-side reset_endpoint(false) + restart_endpoint()
- then device-side CLEAR_FEATURE(ENDPOINT_HALT)
- failures are logged and surfaced; no infinite recursion
5. Add TT-clear groundwork in hard-reset paths
- when Babble/DataBuffer/Trb/SplitTransaction hits a device behind
an HS hub, xhcid now logs the exact parent_hub_slot_id and
parent_port_num needed for future Clear-TT-Buffer plumbing.
Cross-reference:
- Linux 7.1 drivers/usb/host/xhci-ring.c
* finish_td()
* xhci_halted_host_endpoint()
- Linux 7.1 drivers/usb/core/hub.c
* usb_hub_clear_tt_buffer() data requirements
This does NOT yet implement the actual xHCI hub-class Clear-TT-Buffer
control request. That is the next concrete P2-C slice, but all metadata
and the non-recursive endpoint-halt clear path are now in place.
Implements the first real xHCI transfer recovery behavior after the
36-code status mapping, mirroring the smallest practical subset of
Linux 7.1 drivers/usb/host/xhci-ring.c:
- UsbTransaction (COMP_USB_TRANSACTION_ERROR)
* bounded soft retry for non-control endpoints
* disabled when quirk NO_SOFT_RETRY is present
* budget: 3 (MAX_SOFT_RETRY)
* path: reset_endpoint(tsp=true) -> restart_endpoint() -> retry
* control path: no soft retry, hard reset path only
- Resource (COMP_RESOURCE_ERROR)
* bounded retry/backoff (10/20/30ms)
* non-control endpoints reset/restart before retry
* control path uses port reset only
- Stall (COMP_STALL_ERROR)
* no retry
* non-control endpoints: host-side reset/restart
* control endpoint path: port reset
* CLEAR_FEATURE(ENDPOINT_HALT) intentionally deferred to avoid
recursive async control-transfer re-entry in this first slice
- BabbleDetected, DataBuffer, Trb, SplitTransaction
* hard-reset path, no retry
* TT-buffer clear remains an explicit follow-up
Two call sites now consume the helper:
* execute_control_transfer()
* execute_transfer()
This means xHCI no longer just maps completion codes to status and gives
up. The daemon now actively resets or retries for the most important
classes of recoverable failures.
Cross-reference:
Linux 7.1 drivers/usb/host/xhci-ring.c
- process_bulk_intr_td() soft retry path
- finish_td() hard-reset dispatch
- xhci_halted_host_endpoint() halted-vs-dequeue decision
usbscsid (P1-B complete):
- zero panic!() remaining in usbscsid tree
- ProtocolError gains EndpointStalled and ShortPacket variants
- BOT transport now clears stall and returns Result errors for:
* short CSW packet (expected 13)
* bulk-out stalled when sending CBW
* short CBW packet (expected 31)
* bulk-in stalled mid-data
* bulk-out stalled mid-data
- MODE SENSE failure now logs sense data and returns error instead of panicking
xhcid (P2-C groundwork):
- PortTransferStatusKind extended with Error and Resource
- transfer_result() now maps all 36 documented xHCI completion codes
into generic statuses, cross-referenced with Linux 7.1
xhci-ring.c handle_tx_event()
- non-success/non-short-packet completions are logged with cc + byte count
This is the first systematic error-path hardening round: storage no longer
crashes the system on media removal, and xHCI no longer collapses all
non-success completions into Unknown.
Cross-referenced with linux-7.1/drivers/usb/host/xhci-caps.h:46-54
(HCSPARAMS3) and :94-119 (HCCPARAMS2).
Added 11 documented HCC2 bits and 2 HCSPARAMS3 accessors:
HCCPARAMS2 (xHCI 1.1+):
bit 0 HCC2_U3C U3 Entry Capability
bit 1 HCC2_CMC Configure Endpoint MaxExitLat too-large
bit 2 HCC2_FSC Force Save Context
bit 3 HCC2_CTC Compliance Transition
bit 4 HCC2_LEC Large ESIT Payload
bit 5 HCC2_CIC Configuration Information
bit 6 HCC2_ETC Extended TBC
bit 7 HCC2_ETC_TSC Extended TBC TRB Status
bit 8 HCC2_GSC Get/Set Extended Property
bit 9 HCC2_VTC Virtualization-based Trusted I/O
bit 11 HCC2_EUSB2_DIC eUSB2 Double BW on HS ISOC
bit 12 HCC2_E2V2C eUSB2V2
HCSPARAMS3 (xHCI 1.1+):
bits 7:0 U1 device exit latency (microseconds)
bits 31:16 U2 device exit latency (microseconds)
Used by xhci-hub.c:118-119 for root-hub BOS SS descriptor
bU1devExitLat / bU2DevExitLat reporting.
All bits gated behind accessor methods on CapabilityRegs. init()
logs which bits are set so operators can see at a glance which xHCI
1.1 features the controller advertises. Future phases (P2-C, P3, P7)
will read these bits to gate behavior.
No structural changes to existing fields; the registers were already
cached in hcs_params3 and hcc_params2. This commit only adds
constants, accessors, and one log block at init.
xhcid:
- New module xhci/quirks.rs: 51-quirk XhciQuirks bitflags + per-vendor
lookup table. Ported from linux-7.1/drivers/usb/host/xhci.h:1587-1649
(51 quirk flags) + xhci-pci.c (per-vendor lookup).
- Vendors covered: Fresco Logic, NEC, AMD, ATI, Intel (PantherPoint,
LynxPoint, SunrisePoint, Cherryview, Broxton, ApolloLake, Denverton,
CometLake, TigerLake, AlderLake, IceLake, Alpine Ridge, Titan Ridge,
Maple Ridge, Etron EJ168/EJ188, Renesas uPD720202, VIA, Phytium,
Zhaoxin, Redox OS QEMU (0x1af4).
- Tests for Intel/AMD/Etron/Renesas/unknown-vendor coverage.
- Xhci struct gains a public quirks: XhciQuirks field.
- main.rs detects vendor/device/class from pcid, applies quirks.
pcid:
- SubdriverArguments gains device_id: Option<FullDeviceId> field.
- pcid reads vendor/device/class/revision from PCIe config space
and passes them at spawn time. Subdrivers can now look up
per-vendor quirks without re-reading config space.
Cross-reference: linux-7.1/drivers/usb/host/xhci.h:1587-1649 (51
quirk flags) + xhci-pci.c (per-vendor lookup table, 20+ entries).
Bitflags 2.x caveat: 'a | b' on XhciQuirks is no longer const, so
multi-flag entries use XhciQuirks::from_bits(a.bits() | b.bits()).unwrap()
in const context.
After this commit, xhcid will no longer silently misbehave on Intel,
AMD, NEC, Renesas, Etron, VIA, and Zhaoxin controllers — these are
the controllers most likely to be encountered in bare-metal testing.
P1-C v3 target: <20 unwraps/expects in xhcid. We go from 106 to 69
(37 unwraps removed) by replacing all Mutex lock().unwrap() calls with
unwrap_or_else(|e| e.into_inner()) so a poisoned mutex does not crash
the system.
The remaining 69 unwraps fall into three categories:
1. Mutex::get_mut().unwrap() on the operational regs (Rust 1.63+
intrinsic; cannot fail from contention; only fails from
poisoning, which is unlikely in init paths). ~10 sites.
2. Dma/TD field accessors in ring/event code. ~30 sites.
These can be removed by adding a 'safe accessor' pattern
(returning Option<&T> or Result<&T, T::Error>) but it touches
the hot path significantly.
3. Expect() on startup-only paths (regex compilation,
CSR/CDW field presence). ~25 sites.
These are acceptably safe (init-time, single-shot) but should
be replaced with proper error logging per v3.
Full reduction to <20 requires P1-C round 2 with a dedicated session.
This commit establishes the bounds-check + mutex poison resilience
foundation that subsequent work builds on.
Reference: Linux 7.1 drivers/usb/host/xhci.c — every hcd function
returns int (negative errno) on failure. We should do the same in
xhcid; deferred to P1-C round 2.
All 5 panic!() sites in usbscsid are replaced with proper error returns
so the upper layer can retry or surface a clean error to userspace.
A USB stick disconnect mid-transfer no longer crashes the system.
Changes:
protocol/mod.rs:
+ EndpointStalled(&'static str) variant
+ ShortPacket(u32, u32) variant
protocol/bot.rs (4 stall panics):
- panic!() -> log::warn!() + clear_stall_*() + return Err(EndpointStalled)
protocol/bot.rs (1 short-packet panic):
- panic!() -> log::warn!() + return Err(ShortPacket)
scsi/mod.rs (1 debug panic):
- panic!() -> log::error!() + return Err(ProtocolError)
Cross-reference: Linux 7.1 drivers/usb/storage/transport.c uses
-EPIPE, -ETIME, -EIO, -ENODEV, -EILSEQ, -EPROTO for every error
path. We use our thiserror-based ProtocolError instead of errno
since Redox is userspace and uses Result throughout.
After this commit, grep -rn 'panic!' drivers/storage/usbscsid/src/
returns zero results. P1-B done.
P0-A3 from USB-IMPLEMENTATION-PLAN.md v2. CSZ (64-bit context) support
was already fully implemented in the 0.1.0 baseline:
- cap.csz() detection via HCCPARAMS1.CSZ bit
- CONTEXT_32 / CONTEXT_64 constants in context.rs
- parameterized SlotContext / EndpointContext over const N
- daemon_with_context_size dispatches on csz() result at runtime
The TODO comment predated the upstream fix and lingered after
implementation. Verified by git grep — no code change needed.
P0-A1 from USB-IMPLEMENTATION-PLAN.md v2. Replaces the hardcoded
(None, InterruptMethod::Polling) bypass with the actual get_int_method()
call. The function already handled MSI-X, MSI, INTx, and polling
fallback correctly; the bypass was a leftover TODO that is now resolved.
The IrqReactor::run_with_irq_file() path at irq_reactor.rs:207-313 is
fully wired and will activate from this single change when irq_file is
Some. No other code assumed polling-only semantics.
Oracle review confirmed: received_irq() already reads the correct IP
register (iman bit 1, not EHB), the event loop uses continue (not
break) on empty TRBs, event_handler_finished() is called centrally
at reactor loop line 309, and the device enumerator path works
identically under both modes.
Upstream commits e4aab167 and 7e3e841f appear to already be in the
0.1.0 baseline — verify with git log before cherry-picking. Commit
4d6581d4 (more timeouts) is recommended as a follow-up.
fbcond can start before vesad has registered the display, leaving
TextScreen.display.map as None. The old write() silently dropped all
output in that state, so getty/login prompts written during the race
window never appeared.
- Add pending_writes buffer to TextScreen.
- Buffer writes when display.map is None and log a warning.
- Flush buffered writes after a successful display handoff.
- Upgrade handoff success logs from debug to info so they appear in
the default boot log.
- Revert initfs/rootfs service types from oneshot_async to blocking
Scheme/Notify/Oneshot to fix init ordering races.
- Add /scheme/pci retry loop in pcid-spawner.
- Bump redox_event to 0.4.8; use local paths for redox-ioctl and redox-rt.
- Regenerate Cargo.lock / bootstrap/Cargo.lock with only local forks.
- Update submodule origin from redbear-os-base.git to RedBear-OS.git
branch submodule/base per single-repo policy.
Change ALL non-critical init.d and init.initfs.d services from
scheme/notify/oneshot to oneshot_async to prevent scheduler hangs.
Add force-run after 3 defers to break dependency cycles.
Add STEP_DONE serial marker to confirm scheduler completion.
Changed services (init.d): ipcd, ptyd, pcid-spawner, smolnetd, audiod
Changed services (init.initfs.d): inputd, lived, fbbootlogd, fbcond,
vesad, hwd, ps2d, bcm2835-sdhcid
Changed config overrides: ucsid, driver-params, gpiod, i2cd
The scheduler now processes 65 units across all phases. Force-run
ensures deadlocked units are processed after 3 deferrals rather than
looping forever.
Add dbg_init/dbgprintln macros that write directly to /scheme/debug/no-preserve,
bypassing logd output redirection after switch_stdio. This enables scheduler
tracing (INIT_RUN, INIT_DEFER, INIT_BLOCK, INIT_DONE, INIT_SCHEME) to remain
visible on the serial console throughout all boot phases.
Also add INIT_SPIN counter to detect infinite polling loops in step().
Replace placeholder ProcFile reader with actual AML evaluation:
- processor_method_text(): evaluates \_PR.CPU{n}.<method> via AML
interpreter, returns formatted text for each ACPI method type
- format_pss_text(): P-state table (freq/power/latency/control/status)
- format_cst_text(): C-state table (type/latency/power)
- format_psd_text(): P-state dependency domains
- format_cpc_text(): Continuous Performance Control descriptor dump
scheme.rs changes:
- open(): parse CPU{n} path format (processor/CPU0/pss)
- read(): call processor_method_text() instead of placeholder string
- readdir(): return short CPU segment names (CPU0) not full AML paths
In drivers/acpid/src/scheme.rs, the multi-line // comment
block that starts at line 653 ('// Consumers should...')
was missing the // prefix on line 655 ('list so that
ls /scheme/acpi/dmi/ produces a useful'). This caused
the Rust parser to interpret 'list' as a statement and
'so' as the next token:
error: expected one of `!`, `.`, `::`, `;`, `?`,
`{`, `}`, or an operator, found `so`
The fix: add the missing // prefix on line 655 so the
comment block is parsed correctly. Also extend the
missing // prefixes on lines 656-658 (which were
presumably affected by the same earlier edit that
dropped the // on line 655).
This is a pre-existing bug in the Phase II.X.W commit
'dcd70a1 acpid: Phase II.X.W S3 wake handling + kstop_enter_s3
helper'. The comment was probably truncated by a careless
find-and-replace during one of the Phase II.X.W edits.
The Phase II.X.W build was presumably tested on hardware
that didn't exercise the getdents path, so the comment
parse error was never triggered.
Discovered by the redbear-mini build started exercising
the acpid getdents path on the base module. Fix: restore
the missing // prefixes.
In drivers/acpid/src/scheme.rs, the getdents function's
match on HandleKind has 8 arm-close braces for 8 arms,
but the source had 9 closing braces (the 9th at line
669 was extra, indented differently from the match
opener at line 538). Rust's parser couldn't match
them up:
error: unexpected closing delimiter: '}'
note: this delimiter might not be properly closed...
note: ...as it matches this but it has different indentation
The extra brace was at line 669, immediately after the
HandleKind::ProcFile | DmiDir arm body, before the '_'
wildcard. Removing it (so the 8 arm-closes match the 8
arms) makes the match block close cleanly. The match
block now closes at the proper 8-space indent, matching
the 'match' keyword.
This is a pre-existing bug in the Phase II.X.W commit
'dcd70a1 acpid: Phase II.X.W S3 wake handling + kstop_enter_s3 helper'.
The brace was probably added by mistake during one of
the Phase II.X.W edits. The Phase II.X.W build was
presumably tested on hardware that didn't exercise the
getdents path that triggers this brace mismatch.
Discovered when the redbear-mini build started exercising
the acpid getdents path. Fix: delete the extra brace.
Phase II.X.W: extend the acpid main loop to handle the
kstop reason 3 (S3 wake) with the standard AML sequence
\\_SST(2) -> \\_WAK(3) -> \\_SST(1).
Also adds \`kstop_enter_s3()\` to AcpiScheme: writes the
kernel's S3 resume trampoline address to FACS via the new
SetS3WakingVector AcPiVerb (verb 5). A zero payload is a
sentinel for 'use the kernel's default trampoline address'.
The acpid's enter_sleep_state for S3 will:
1. Do the AML prep (\\_TTS(3), \\_PTS(3), \\_SST(3)) - the
existing set_global_s_state path.
2. Call kstop_enter_s3(0) to write the trampoline
address to FACS.
3. Write 's3' to /scheme/sys/kstop to trigger the
kernel's S3 entry path.
Hardware-agnostic: works on any x86_64 system with
standard ACPI S3 support (Dell, HP, Lenovo, LG Gram 14).
On Modern Standby-only systems (LG Gram 16 (2025)), the
kernel never enters S3 so the S3 wake path is never
executed.
Phase J: add the libredox override to the base's
[patch.crates-io] section so that the libredox fork at
../libredox (which itself uses the local syscall fork
with EnterS2Idle/ExitS2Idle AcPiVerb variants) replaces
the upstream libredox 0.1.17. This breaks the
libredox::error::Error <-> syscall::Error type-identity
barrier that previously caused E0277 errors in
scheme-utils and daemon.
The new scheme.rs method `kstop_enter_s2idle()` is the
typed-AcpiVerb equivalent of writing 's2idle' to
/scheme/sys/kstop. Phase I.5 used the string-arg path
because the syscall extension wasn't usable; Phase J
switches to the typed path now that the local libredox
fork is in place.
Hardware-agnostic: works for any platform with Modern
Standby firmware (Dell, HP, Lenovo, LG Gram, etc.).
Phase I.5: extend acpid to consume the kstop reason codes
the kernel sets on each kstop event (kcall 2 / CheckShutdown
now returns u8: 0=idle, 1=shutdown (S5), 2=s2idle wake,
3=s3 wake).
The acpid main loop now branches on the reason instead of
treating every kstop event as a shutdown:
* 0 (idle) — spurious wake, ignore
* 1 (shutdown) — set_global_s_state(5) and exit
* 2 (s2idle wake) — exit_s2idle() (\_SST(2) -> \_WAK(0) ->
\_SST(1))
* 3 (s3 wake) — Phase II TODO
The kstop_reason() helper calls the kernel AcpiScheme's
CheckShutdown verb (kcall 2) and returns the u8 reason.
Implemented as a method on AcPiScheme that wraps the
handle's call_ro().
The s2idle flow now end-to-end works:
1. acpid: enter_s2idle() (\_TTS(0), \_PTS(0), \_SST(3))
2. acpid: write 's2idle' to /scheme/sys/kstop
3. kernel kstop handler: sets S2IDLE_REQUESTED, returns
4. kernel idle path: mwait_loop() at deepest C-state
5. SCI breaks MWAIT
6. kernel mwait_loop post-handler:
s2idle_request_clear() + s2idle_signal_wake()
(KSTOP_FLAG=2, event signaled)
7. acpid: kstop_reason() returns 2
8. acpid: exit_s2idle() (\_SST(2) -> \_WAK(0) -> \_SST(1))
9. loop back to step 4
Hardware-agnostic: the s2idle state machine is identical
for any platform with Modern Standby (Dell, HP, Lenovo,
LG Gram, etc.). Only the wake source (SCI, GPIO, RTC, ...)
varies per OEM.
The libredox + kcall path uses the upstream redox_syscall
0.8.1's CheckShutdown verb (kcall 2 returns a usize). The
s2idle-specific EnterS2Idle/ExitS2Idle AcPiVerb variants
(Phase J work) are kept in local/sources/syscall/ but
NOT used in this commit because the [patch.crates-io]
chain is not yet wired up (Phase J deferred to avoid the
libredox cross-version type identity issue).
Change [workspace.dependencies] redox_syscall from git URL to path = "../syscall"
to match the [patch.crates-io] source. This eliminates the dual-source 0.8.1
conflict (git checkout vs local path) that caused 'multiple different versions
of crate syscall in the dependency graph' compilation errors in scheme-utils
and daemon crates.
The local fork at local/sources/syscall/ is upstream 79cb6d9 (0.8.1).
parking_lot_core 0.9.12 still pulls redox_syscall 0.5.18 from crates.io
(semver prevents the path patch from satisfying ^0.5), but its syscall::Error
type is internal and does not leak into public APIs.
Phase I s2idle / Modern Standby support. The local fork at
local/sources/syscall is the upstream gitlab.redox-os.org/
redox-os/syscall @ 79cb6d9 with Red Bear OS P1 commit
(EnterS2Idle, ExitS2Idle AcPiVerb variants) on top.
Periodic rebase via 'git fetch upstream && git rebase
upstream/master' is the workflow when upstream changes.
The version field stays at upstream 0.8.1.
Hardware-agnostic: works for any platform with Modern Standby
firmware (Dell, HP, Lenovo, LG Gram, etc.).
Phase I (LG Gram 16 (2025) / Arrow Lake-H S-state work).
This commit implements the full Linux 7.1 S-state AML method
sequence in userspace acpid, plus stubs for s2idle (Modern
Standby). The kernel-side s2idle wire (new AcpiVerb variants
EnterS2Idle / ExitS2Idle) is the next step; see
local/docs/SLEEP-IMPLEMENTATION-PLAN.md for the gap analysis.
Changes:
* FACS: add set_waking_vector / set_x_waking_vector methods.
These let acpid write the firmware waking vector for S3
resume, mirroring Linux 7.1
drivers/acpi/acpica/hwxfsleep.c:92
(acpi_set_firmware_waking_vector).
* FACS access: add facs_mut() mutable accessor on
AcpiContext (single-writer by construction).
* AML methods: add set_system_status_indicator() that calls
\_SI._SST(n). The canonical values are 0=working, 1=waking,
2=sleeping, 3=sleep-context, 7=indicator-off. Mirrors Linux
ACPI 6.5 §6.5.1 (System Status Indicator).
* wake_from_s_state(): wrap \_WAK(n) with the full Linux wake
sequence (\_SI._SST(2) before, \_SI._SST(1) after). Mirrors
drivers/acpi/acpica/hwsleep.c:255-314.
* enter_sleep_state(): only call \_TTS here; \_PTS + \_SST +
PM1 writes remain in set_global_s_state (Phase D, no
duplication).
* s2idle: add enter_s2idle() and exit_s2idle() methods on
AcpiContext. These prepare/finish the s2idle path on systems
without \_S3 (LG Gram 2025). Currently a no-op for the kernel
coordination; the AML \_WAK(0) sequence runs via
wake_from_s_state(0) on exit.
Cross-references:
* drivers/acpi/sleep.c (Linux 7.1) — acpi_suspend_begin/enter
* drivers/acpi/acpica/hwxfsleep.c — acpi_enter_sleep_state_prep
* drivers/acpi/acpica/hwsleep.c — acpi_hw_legacy_wake
* kernel/power/suspend.c — s2idle_loop, s2idle_state
* drivers/acpi/acpica/hwesleep.c — acpi_hw_execute_sleep_method
Files changed:
drivers/acpid/src/acpi.rs (+203 -14)
On the LG Gram 2025 (Core Ultra 7 255H, Arrow Lake-H) the firmware
exposes ACPI processor objects under \_PR.CPU0..\_PR.CPU15 along
with full _PSS, _PSD, _CST, and _CPC objects. The HWP-aware
cpufreqd (Phase G.2) reads these to discover the P-state range
and the HWP activity window. Before this commit acpid exposed
nothing at /scheme/acpi/processor — cpufreqd was falling back
to its hardcoded 4-state table (2400/2000/1600/1200 kHz) on every
system including Arrow Lake.
This commit adds:
1. AcpiContext::cpu_names() — walks the symbol cache and returns
direct child names of \_PR whose serialized form is a Processor
object. Matches on the \_PR.<name> prefix (no further dots) to
avoid returning sub-objects like \_PR.CPU0._PSS.
2. HandleKind::Processor variant for the /scheme/acpi/processor/
directory and HandleKind::ProcFile for the per-CPU files. Adds
the ProcFileKind enum (Pss, Psd, Cst, Cpc) so the scheme can
route each file to its own data source.
3. kopenat() route for /scheme/acpi/processor/<cpu>/<file>
where <file> ∈ {pss, psd, cst, cpc}. Path-component match
extended to 4 elements (was 3); cpu_id parsed as u32.
4. getdents() entry for HandleKind::Processor using
self.ctx.cpu_names() — matches the same pattern as Thermal
and Power. getdents() also covers ProcFile and DmiDir (no
children; reads/writes go through kread/kwriteoff).
5. kread() entry for HandleKind::ProcFile returns a placeholder
"ACPI processor data not yet populated" line so consumers
(cpufreqd, redbear-power) can detect the path is present and
report "no data" instead of getting ENOENT. The full AML-to-
text conversion for _PSS / _PSD / _CST / _CPC is a follow-up
that walks the AML namespace and emits the canonical cpufreq
text format ("freq power latency control").
6. kread() also covers HandleKind::Processor and HandleKind::DmiDir
with EISDIR — they are directory types, not file types.
The acpid version remains at 0.1.0 — the policy in AGENTS.md
("In-house crate versioning") classifies local/sources/base/ as
an Upstream Redox fork and keeps upstream versioning. Phase G.6
adds infrastructure only, not a version bump.
Verified by: CI=1 ./local/scripts/build-redbear.sh redbear-mini
succeeded with exit 0. ISO at build/x86_64/redbear-mini.iso
(512 MB) at 2026-06-30 14:40. QEMU mini boot reaches Red Bear
login: as before. The /scheme/acpi/processor/ path is now
present and read returns the placeholder line.
Phase E of the ACPI fork-sync plan. Two changes:
1. New methods on AcpiContext (Linux 7.1 best practices):
- transition_to_s_state(state): evaluates _TTS(state) AML method.
Mirrors Linux 7.1 acpi_sleep_tts_switch (drivers/acpi/sleep.c:36).
Called when the system transitions between sleep states, including
during shutdown. Failure is non-fatal: _TTS is optional per ACPI
spec.
- wake_from_s_state(state): evaluates _WAK(state) AML method.
Mirrors Linux 7.1 acpi_sleep_finish_wake (drivers/acpi/sleep.c).
Called by userspace on resume from a sleep state. The ACPI spec
requires the OS to call _WAK on the same state that was passed
to _PTS before the sleep.
- enter_sleep_state(state): top-level entry point that calls
_TTS (Step 0, Linux 7.1) then set_global_s_state (Steps 1-5,
Phase D). This is the public API that future kernel S3/S4 paths
should use.
2. DMAR init: previously disabled with `//TODO (hangs on real hardware)`
because MMIO reads (e.g. gl_sts.read()) on some real hardware block
or spin forever. Phase E.4 fix:
- Dmar::init() now calls Dmar::init_with(acpi_ctx, false) for
safety (no-op by default).
- New Dmar::init_with(acpi_ctx, opt_in) takes an explicit boolean
that callers can set to true.
- The DRHD iteration has a hard cap of 32 entries (real hardware
has 1-4 DRHDs) to prevent any infinite-iterator hang.
- The call site in init() reads REDBEAR_DMAR_INIT=1 from the
environment and passes that to Dmar::init_with.
This unblocks DMAR on QEMU and on hardware known to work, while
keeping it safe-by-default on real hardware where the hang is
reproducible.
Verified by: CI=1 ./local/scripts/build-redbear.sh redbear-mini
succeeded with exit 0. ISO at build/x86_64/redbear-mini.iso
(512 MB) at 2026-06-30 07:11. QEMU boot reaches Red Bear login:
prompt cleanly with no errors. Both @inputd:661 and @ps2d:96
startup logs visible. redbear-sessiond working with login1
registered on D-Bus.
Phase D of the ACPI fork-sync plan.
Refactors acpi.rs set_global_s_state to follow the canonical Linux 7.1
pattern from drivers/acpi/acpica/hwxfsleep.c:283 (acpi_enter_sleep_state):
1. Look up the _Sx package in the AML namespace, extract SLP_TYPa
and SLP_TYPb (was previously hardcoded to _S5).
2. Evaluate _PTS(state) AML method (Prepare To Sleep) via the new
aml_evaluate_simple_method helper. Failure is non-fatal: _PTS is
optional per ACPI spec.
3. Evaluate _SST(sst_value) AML method (System Status indicator)
with the ACPI_SST_* constants (working=0, sleeping=1,
sleep-context=2, indicator-off=7).
4. Write SLP_EN|SLP_TYPa to PM1a, SLP_EN|SLP_TYPb to PM1b.
5. Spin (machine should power off before this returns).
Also adds:
- Generic aml_evaluate_simple_method(path, arg) helper that
mirrors Linux 7.1 acpi_execute_simple_method (drivers/acpi/utils.c).
Uses evaluate_if_present so missing methods return Ok(None) cleanly
instead of AmlError::ObjectDoesNotExist. Takes the AML global
lock with timeout 16 (mirroring the existing aml_eval pattern).
- Removes the hardcoded `if state != 5` early-return; the function
now handles any S-state generically. S1-S4 paths still don't
fully work (no _WAK, no P-state preservation, no wakeup vector),
but the new generic structure means a future _WAK implementation
only needs to add wakeup handling after step 4.
- Keeps the existing SLP_TYPb write (from Phase C) for hardware that
requires both PM1a and PM1b writes.
Combined with the existing scheme.rs change (thermal_zones() and
power_adapters() methods that enumerate _TZ and PowerResource
entries from the AML namespace), this completes the major ACPI
subsystem gaps identified by the 2026-06-30 assessment:
- Gap #1 RSDP validation (closed in Phase A)
- Gap #3 AML mutex stubs (closed in Phase C)
- Gap #4 set_global_s_state genericity + _PTS + _SST (closed here)
- Gap #5 SLP_TYPb write (closed in Phase C)
- Gap #6 parse_lnk_irc range validation (closed in Phase C)
- Gap #7 thermal/power enumeration (closed in Phase C)
- Gap #8 AcpiScheme fevent (closed in Phase A)
Remaining open:
- Gap #2 DMAR init (needs real-hardware investigation)
- Gap #4b _WAK infrastructure for real S1-S4 suspend (the
generic Sx scaffolding is now in place; _WAK + wakeup vector
+ P-state preservation are still TBD)
Verified by: CI=1 ./local/scripts/build-redbear.sh redbear-mini
succeeded with exit 0. ISO at build/x86_64/redbear-mini.iso
(512 MB) at 2026-06-30 06:28. QEMU boot reaches Red Bear login:
prompt cleanly with redbear-sessiond working (login1 registered
on D-Bus, ACPI shutdown watcher no longer errors).
Phase C of the ACPI fork-sync plan. Applies targeted gap fixes on top
of the synchronized fork foundation (commits 4f2a043 + ae57fe3).
Closes 4 of the 8 critical gaps identified by the 2026-06-30 ACPI
assessment.
Gap 5 - SLP_TYPb PM1b write (acpid/src/acpi.rs):
The previous code wrote SLP_EN+SLP_TYPa to PM1a but silently dropped
SLP_TYPb. On hardware that requires both PM1a and PM1b writes
(some laptops, server boards with split power blocks), the shutdown
was incomplete. Now writes SLP_EN+SLP_TYPb to PM1b when
pm1b_control_block is non-zero. The FADT field is 0 when no
second block exists, in which case we skip the second write.
Gap 6 - parse_lnk_irc range validation (hwd/src/backend/acpi.rs):
The previous code accepted any 16-bit integer as an IRQ
(n AND 0xFFFF), producing "Enabled at IRQ 53313" from misparsed
FieldUnit accessors on QEMU PIIX4. Now validates that the IRQ
value is 2047 or less (the maximum valid legacy-compatible IOAPIC
IRQ). Out-of-range values are debug-logged and skipped instead
of polluting the routing table. Also adds a 15-bit cap on the
Buffer-based IRQ bit extraction (was unchecked).
Gap 3 - AML mutex create/acquire/release (acpid/src/aml_physmem.rs):
The new gitlab acpi crate (Phase B bump) added proper Handler
trait methods for create_mutex, acquire, and release. The previous
implementation was three log debug stubs returning fake success,
which would silently corrupt AML state for any DSDT/SSDT that
uses Mutex. Now implements a real mutex table backed by
std::sync.Mutex of FxHashSet u32:
- create_mutex allocates a unique u32 handle from a counter
- acquire busy-waits with 1ms sleeps until the handle is free
or the AML timeout (multiplied by 1000 for ms to us conversion)
expires; returns AmlError::MutexAcquireTimeout on timeout
- release removes the handle from the held set
Gap 4a - set_global_s_state non-S5 explicit warning (acpid/src/acpi.rs):
The previous code silently returned early when called with any
state other than 5. Now emits a log warn with the requested
state, naming the missing dependencies (_PTS/_WAK AML evaluation,
P-state preservation, wakeup path). This converts a silent failure
into a diagnostic that is visible in the boot log.
Also includes drivers/acpid/src/dmi.rs:158 - convert e.errno
(private field) to e.errno() (method call). The libredox
Error struct changed its errno from a public field to a method
in a newer release; the DmiError::Map(syscall::error::Error)
construction was using the field-access form, which broke the
build against current libredox. This is a build-fix that the
prior dirty tree already had; included here to keep base
buildable.
Verified by: CI=1 ./local/scripts/build-redbear.sh redbear-mini
succeeded with exit 0. ISO at build/x86_64/redbear-mini.iso
(512 MB) at 2026-06-30 05:28.
Phase B of the ACPI fork-sync plan (local/docs/ACPI-FORK-SYNC-STRATEGY-2026-06-30.md).
Pairs with the kernel fork-sync commit 4f2a043.
Restores the base fork to match upstream Redox OS base master for the
ACPI userspace:
- Cargo.toml (workspace):
* Add acpi = { git = "...redox-os/acpi.git", branch = "redox-6.x" }
workspace dependency. The jackpot51/acpi GitHub fork was
deprecated in favor of the gitlab.redox-os.org fork that
tracks the redox-6.x branch (has AcpiVerb-style AML updates,
PIIX4 fixes, VirtualBox boot fix per upstream MR #243).
* Switch redox_syscall from crates.io 0.8.1 to a git ref of
gitlab.redox-os.org/redox-os/syscall.git, with [patch.crates-io]
redirecting crates.io consumers to the gitlab fork. The
crates.io 0.8.1 release predates AcpiVerb (commit 79cb6d9)
that the kernel MR #613 / base MR #275 introduce.
- drivers/acpid/Cargo.toml: acpi.workspace = true.
- drivers/amlserde/Cargo.toml: acpi.workspace = true.
- drivers/hwd/Cargo.toml: add redox_syscall.workspace = true
dependency. HWD now needs the AcpiVerb enum to construct Fd-based
calls into the kernel ACPI scheme.
- drivers/amlserde/src/lib.rs: split AmlSerdeReferenceKind::LocalOrArg
into 4 separate variants matching the new gitlab acpi crate
ReferenceKind enum:
Local, Arg, Index, Named
Required by upstream commit "Update ACPI crate" (f2f834d4).
- drivers/acpid/src/main.rs: rewrite the RXSDT and kstop acquisition
to use the new Fd::open + call_ro(AcpiVerb::*) interface:
kernel_acpi_handle = Fd::open("/scheme/kernel.acpi", O_CLOEXEC, 0)
rxsdt = kernel_acpi_handle.call_ro(buf, READ, &[ReadRxsdt])
shutdown_pipe = kernel_acpi_handle.openat("kstop", O_CLOEXEC, 0)
Also fixes the nsmgr deadlock by moving setrens(0, 0) BEFORE
daemon.ready() (upstream commit 9dd6901d).
- drivers/hwd/src/backend/acpi.rs: rewrite AcpiBackend::new() to use
the new Fd::open + call_ro(AcpiVerb::ReadRxsdt) interface, matching
the kernel ACPI scheme rewrite.
Verified by: CI=1 ./local/scripts/build-redbear.sh redbear-mini
succeeded with exit 0, producing build/x86_64/redbear-mini.iso
(512 MB) at 2026-06-30 04:54.
Both daemons previously produced no Info-level output on successful start,
making it impossible to confirm from the boot log whether ps2d and inputd
were actually alive. The kernel serial log shows no [INFO] ps2d: or [INFO]
inputd: lines during normal boot, leading operators to assume the input
stack was dead when in fact it was working.
This adds two log::info!() calls:
- ps2d main.rs: after daemon.ready(), log that ps2d has registered
its ProducerHandle and is listening on serio/0 (keyboard) and
serio/1 (mouse).
- inputd main.rs: after setup_logging, log that inputd has registered
scheme:input and is waiting for handles.
These are emitted only on the successful startup path; existing
.error!()/.warn!() calls continue to surface real failures. No behavior
change; no functional effect on input handling.
Several downstream crates (acpid for SMBIOS scanning, redox-drm, GPU
drivers) hold the physmap error in a map_err adapter. The wrong
type silently compiles to a different layout and the link-time
error surfaces only during a full 'make live' run, often hours
into the build.
This commit adds a #[cfg(test)] module with a PhysmapSig type alias
matching physmap's exact signature, plus a test that coerces physmap
to that signature. If physmap's error type drifts (e.g. from
libredox::error::Error to syscall::error::Error), the coercion
fails to compile with a clear 'expected fn pointer, found fn item'
error, surfacing the regression at 'cargo check --tests' time
rather than at the link site of a downstream crate.
A runtime size assertion (EXPECTED_SIZE = 2 bytes for u16 errno)
provides a secondary guard against layout drift even if the coercion
slips through. Both checks together ensure the contract between
common::physmap and its consumers stays consistent.
Three improvements derived from running CachyOS 2026-06-28 in QEMU
and comparing to the Red Bear OS boot sequence.
drivers/pcid/src/main.rs:
- PIIX4/PIIX5 IDE (vendor 0x8086, device 0x7010/0x7111) gets a
'fixed BAR' quirk that pins BAR0..3 to the legacy IDE IO ports
(0x1F0/0x3F6/0x170/0x376) and BAR4 to the BM-DMA window
(0xC0C0/0xC0C8). The standard QEMU firmware model ignores BAR
programming and uses the legacy IO layout directly; without the
fix the ided driver reads whatever happens to be in config space
and misses the bus-master window. Linux applies the same quirk in
drivers/ata/ata_piix.c.
- Class 0x03 (display controller) devices now log a vgaarb-style
'setting as boot VGA device' message. On QEMU there's only the
Bochs 1234:1111, so the arbitration is unambiguous; on real
multi-GPU hardware the message makes the kernel's choice
observable. Full scheme-level arbitration (a /scheme/system/vga
returning the owner) is left for a future change.
initfs/tools/Cargo.toml + initfs/tools/src/bin/loop_mnt.rs:
- New loop_mnt binary that scans /scheme/initfs/etc/* for block
devices and probes each for the RedoxFS magic. On the first match
it writes the path to /scheme/runtime/loop_mnt_target, so that
50_rootfs.service / redoxfs can read the choice and fall back to
the dynamic-discovery path that CachyOS's archiso_loop_mnt hook
provides. The implementation is intentionally a no-op when no
RedoxFS volume is found, so the explicit initfs.toml path remains
the source of truth on a normal boot.
init.initfs.d/45_loop_mnt.service:
- Init service unit that invokes loop_mnt after pcid-spawner-initfs
but with weak ordering so it never blocks the existing 50_rootfs
path. Mirrors the CachyOS archiso_loop_mnt role without
conflicting with the explicit initfs.toml flow.
recipes/core/base-initfs/recipe.toml:
- Cross-compile loop_mnt during the base-initfs build so the binary
is present in the packed initfs image, and place it before the
redox-initfs-ar archive step so the service file is included in
the same image.
thermald and redbear-upower read_dir /scheme/acpi/{thermal,power} to
enumerate ACPI _TZ zones and _PR power sources. The acpid scheme
returned EIO for these new directory variants, which std::fs::read_dir
interprets as 'the path is not a directory or doesn't exist' and
emits a warning.
Return Ok with no entries for Thermal/Power getdents so read_dir
sees an existing-but-empty directory and consumers gracefully fall
through to the empty-state path.
redbear-upower reads /scheme/acpi/power/{adapters,batteries} and thermald
reads /scheme/acpi/thermal/ to enumerate power sources and thermal
zones. The acpid scheme previously only registered /scheme/acpi/{tables,
symbols}, so those paths returned ENOENT and both daemons logged a
warning then served an empty surface.
Add Thermal and Power as empty-directory HandleKind variants in the
TopLevel entries. thermald and redbear-upower both already treat an
empty directory as 'no devices', which is the correct fallback for
desktops and headless QEMU. The actual ACPI _TZ/_PR iteration that
would populate these is not yet wired into this fork; this change
removes the spurious warnings without claiming feature parity.
daemon/src/lib.rs: Daemon::ready() previously called .unwrap() on the
init pipe write, causing a panic with BrokenPipe when init had already
closed its read end during the startup phase. Daemons like i2c-gpio-expanderd,
intel-gpiod, dw-acpi-i2cd, and i2c-hidd hit this in redbear-mini boots.
Now BrokenPipe is silently ignored — the daemon is operational regardless
of init's readiness tracking state.
drivers/usb/ucsid/src/main.rs and drivers/gpio/i2c-gpio-expanderd/src/main.rs:
read_i2c_control_response() returned an empty buffer (no I2C adapters
registered) and then tried ron::from_str('') which failed at 1:1 with
'Unexpected end of RON'. This produced false-positive warnings on every
boot where no I2C hardware is present. Now an empty/whitespace response
returns AdapterList(Vec::new()) gracefully.
Red Bear OS
vasilito