Bug fix: endpoint numbers were computed as per-interface positions, but
xhcid keys endpoints by GLOBAL index across all interfaces of the
configuration. On two-interface ACM devices (comm interrupt-IN first),
the driver opened (interrupt-IN, bulk-IN) as (bulk_in, bulk_out) — read
from the interrupt endpoint and wrote to the IN endpoint. Endpoints are
now counted across all interfaces in configuration order, exactly as
xhcid's PortState::get_endp_desc does.
P6-A expansion (Linux 7.1 cdc-acm.c reference):
- SEND_BREAK (0x23) control request
- SERIAL_STATE monitoring: poll the comm interface's interrupt-IN
endpoint on a dedicated thread, parse the 8-byte header + 2-byte UART
state bitmap (CDC 1.1 6.3.5): DCD/DSR/break/RI/framing/parity/overrun,
log transitions
- scheme gains a read-only 'state' file reporting the current line
state (dcd=.. dsr=.. ...) for getty/terminal consumers
Verified: cargo check -Z build-std --target x86_64-unknown-redox clean,
no new warnings. Runtime validation needs an ACM device (QEMU has no
CDC ACM emulation; FTDI/Arduino on bare metal or passed through).
vasilito
f505d18a89