PR/57662 CVS commit: [netbsd-10] src/sys/dev/usb

["Martin Husemann" <martin%netbsd.org@localhost>]

The following reply was made to PR port-i386/57662; it has been noted by GNATS.

From: "Martin Husemann" <martin%netbsd.org@localhost>
To: gnats-bugs%gnats.NetBSD.org@localhost
Cc: 
Subject: PR/57662 CVS commit: [netbsd-10] src/sys/dev/usb
Date: Mon, 30 Oct 2023 17:45:11 +0000

 Module Name:	src
 Committed By:	martin
 Date:		Mon Oct 30 17:45:10 UTC 2023
 
 Modified Files:
 	src/sys/dev/usb [netbsd-10]: ehci.c
 
 Log Message:
 Pull up following revision(s) (requested by riastradh in ticket #440):
 
 	sys/dev/usb/ehci.c: revision 1.318
 	sys/dev/usb/ehci.c: revision 1.319
 
 ehci(4): Fix cv_timedwait loop in ehci_sync_hc.
 
 Stop when
         now - starttime >= delta,
 i.e., when at least delta ticks have elapsed since the start, not
 when
         endtime - now > delta,
 i.e., more than delta ticks _remain_ to sleep, which is never going
 to happen (except on arithmetic overflow).
 
 As is, what will happen in the case that should time out is that we
 wake up after delta ticks, and find now = getticks() is exactly
 endtime, so we retry cv_timedwait with timo=(endtime - now)=0 which
 means sleep indefinitely with no timeout as if with cv_wait.
 
 PR port-i386/57662
 
 ehci(4): Fix bug causing missed wakeups since ehci.c 1.308.
 
 For reasons beyond me now, I used cv_signal on the same cv that is
 used to wait for the doorbell to be available _and_ to wait for the
 host controller to acknowledge the doorbell.  Which means when the
 host controller acknowledges the doorbell, we might wake some thread
 waiting for the doorbell to be available -- and leave the thread
 waiting for the doorbell acknowledgment hanging indefinitely.
 
 PR port-i386/57662
 
 
 To generate a diff of this commit:
 cvs rdiff -u -r1.315.2.1 -r1.315.2.2 src/sys/dev/usb/ehci.c
 
 Please note that diffs are not public domain; they are subject to the
 copyright notices on the relevant files.