Implement the actual port suspend/resume path using the USB 3.0
link state definitions, cross-referenced with Linux 7.1
xhci-hub.c: xhci_set_link_state().
port.rs:
- Port::set_link_state(state): writes PLS + PORT_LINK_STROBE
after clearing all RW1CS/RW1S bits to neutral
- Port::suspend(usb3): transitions to XDEV_U3
- Port::resume(): transitions to XDEV_U0
mod.rs:
- Xhci::suspend_port(port_id): detects USB 3.0 vs USB 2.0
from port speed field, calls Port::suspend()
- Xhci::resume_port(port_id): calls Port::resume()
Each operation locks ports, validates the port index, and
logs the transition at info level.
This means the xhci controller can now transition individual
USB 3.0 root-hub ports to U3 (suspend) and back to U0 (resume),
which is the core mechanism for USB power management. The
autosuspend timer that triggers these transitions automatically
is P7-C slice 2.
First USB 2.0 Link Power Management implementation slice,
cross-referenced with Linux 7.1 drivers/usb/host/xhci.c:
xhci_set_usb2_hardware_lpm() and xhci-port.h.
capability.rs: HCCPARAMS1 feature bit detection (Linux: HCC_*)
- HCC_PPC (bit 3): Port Power Control
- HCC_PIND (bit 4): Port Indicators
- HCC_LHRC (bit 5): Light HC Reset
- HCC_LTC (bit 6): Latency Tolerance Messaging
- HCC_NSS (bit 7): No Secondary Stream ID
- HCC_SPC (bit 9): Short Packet Capability
- HCC_CFC (bit 11): Contiguous Frame ID
- HCC_HLC (bit 19): USB 2.0 Hardware LPM Capability (xHCI 1.1+)
port.rs: PORTHLPMC register bit definitions (Linux: xhci-port.h)
- PORT_HLE: Hardware LPM Enable (bit 16)
- PORT_HIRD_MASK, PORT_L1_TIMEOUT_MASK, PORT_BESLD_MASK
- XHCI_DEFAULT_BESL = 4, XHCI_L1_TIMEOUT = 512us
- Port::enable_lpm(hird, l1_timeout): programs PORTHLPMC
- Port::disable_lpm(): clears PORTHLPMC
mod.rs:
- init() logs HCC1.HLC capability
- LPM-aware quirk XHCI_HW_LPM_DISABLE gates LPM enable
This makes USB 2.0 ports capable of entering L1 low-power link
state when both the host controller and device support it.
Actual LPM negotiation with devices (BESL, HIRD calculation,
Evaluate Context for MEL) is deferred to P7 slice 2.
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.
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.
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