CVS commit: src/sys

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Wed Mar  9 22:17:41 UTC 2022

Modified Files:
        src/sys/arch/mips/adm5120/dev: ahci.c
        src/sys/dev/ic: sl811hs.c
        src/sys/dev/usb: ehci.c motg.c ohci.c uhci.c usbdivar.h usbroothub.c
            xhci.c

Log Message:
usb: Provisionally release bus lock around ubm_rhctrl.

This isn't quite correct, but it avoids a deadlock:

- *_roothub_ctrl holds bus lock, waits in usb_delay_ms for kpause
- softint waits for bus lock, holds up kpause wakeup

The deadlock is new since recent changes to hold the bus lock over
upm_start/upm_transfer.  Making this change regresses to other
problems:

- *_suspend/resume and *_roothub_ctrl often touch the same portsc
   registers

- roothub_ctrl_abort needs to wait for ubm_rhctrl to complete.

  When the bus lock was held across both, a noop served here, but we
  can't hold the bus lock across both, so that doesn't work.

However, these problems -- which we've had for a long time -- seem to
be less bad than the deadlock.  So let's avoid the deadlock for now
and then work out another way to serialize suspend/resume/rhctrl and
aborts.

Candidate fix for PR kern/56739.


To generate a diff of this commit:
cvs rdiff -u -r1.30 -r1.31 src/sys/arch/mips/adm5120/dev/ahci.c
cvs rdiff -u -r1.110 -r1.111 src/sys/dev/ic/sl811hs.c
cvs rdiff -u -r1.305 -r1.306 src/sys/dev/usb/ehci.c
cvs rdiff -u -r1.40 -r1.41 src/sys/dev/usb/motg.c
cvs rdiff -u -r1.321 -r1.322 src/sys/dev/usb/ohci.c
cvs rdiff -u -r1.311 -r1.312 src/sys/dev/usb/uhci.c
cvs rdiff -u -r1.134 -r1.135 src/sys/dev/usb/usbdivar.h
cvs rdiff -u -r1.13 -r1.14 src/sys/dev/usb/usbroothub.c
cvs rdiff -u -r1.158 -r1.159 src/sys/dev/usb/xhci.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.