History log of /freebsd-10-stable/sys/dev/usb/usb_request.c
Revision Date Author Comments
# 343136 18-Jan-2019 hselasky

MFC r342778:
Reduce timeout for reading the USB HUB port status to 1000ms and try to filter
out dead USB HUB devices by implementing an error counter, so that the USB
enumeration thread does not spend all its time reading from non-responding
devices, blocking user-space access in the end.

Tested by: Matthias Apitz <guru@unixarea.de>
Sponsored by: Mellanox Technologies


# 336887 30-Jul-2018 hselasky

MFC r335700:
Improve the kernel's USB descriptor reading function.
Some USB devices does not allow a partial descriptor readout.

Found by: bz@
Sponsored by: Mellanox Technologies


# 305734 12-Sep-2016 hselasky

MFC r305421:
Resolve deadlock between device_detach() and usbd_do_request_flags()
by reviving the SX control request lock and refining which lock
protects the common scratch area in "struct usb_device".

The SX control request lock was removed by r246759 because it caused a
lock order reversal with the USB enumeration lock inside
usbd_transfer_setup() as a function of r246616. It was thought that
reducing the number of locks would resolve the LOR, but because some
USB device drivers use usbd_do_request_flags() inside callback
functions, like in taskqueues, a deadlock may occur when these are
drained from device_detach(). By restoring the SX control request
lock usbd_do_request_flags() is allowed to complete its execution
when a USB device driver is detaching. By using the SX control request
lock to protect the scratch area, the LOR introduced by r246616 is
also resolved.

Bump the FreeBSD version while at it to force recompilation of all USB
kernel modules.

Found by: avos@


# 261105 24-Jan-2014 hselasky

MFC r260588 and r260589:
- Separate I/O errors from reception of STALL PID.
- Implement better error recovery for Transaction Translators, TTs,
found in High Speed USB HUBs which translate from High Speed USB into
FULL or LOW speed USB. In some rare cases SPLIT transactions might get
lost, which might leave the TT in an unknown state. Whenever we detect
such an error try to issue either a clear TT buffer request, or if
that is not possible reset the whole TT.


# 261105 24-Jan-2014 hselasky

MFC r260588 and r260589:
- Separate I/O errors from reception of STALL PID.
- Implement better error recovery for Transaction Translators, TTs,
found in High Speed USB HUBs which translate from High Speed USB into
FULL or LOW speed USB. In some rare cases SPLIT transactions might get
lost, which might leave the TT in an unknown state. Whenever we detect
such an error try to issue either a clear TT buffer request, or if
that is not possible reset the whole TT.