Date: Wed, 13 Sep 2006 15:48:15 +0000 (UTC) From: Scott Long <scottl@FreeBSD.org> To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org Subject: cvs commit: src/sys/kern subr_witness.c src/sys/dev/syscons scmouse.c syscons.c syscons.h Message-ID: <200609131548.k8DFmFQS013002@repoman.freebsd.org>
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scottl 2006-09-13 15:48:15 UTC
FreeBSD src repository
Modified files:
sys/kern subr_witness.c
sys/dev/syscons scmouse.c syscons.c syscons.h
Log:
Introduce a spinlock for synchronizing access to the video output hardware
in syscons. This replaces a simple access semaphore that was assumed to be
protected by Giant but often was not. If two threads that were otherwise
SMP-safe called printf at the same time, there was a high likelyhood that
the semaphore would get corrupted and result in a permanently frozen video
console. This is similar to what is already done in the serial console
drivers.
Revision Changes Path
1.41 +4 -4 src/sys/dev/syscons/scmouse.c
1.446 +17 -14 src/sys/dev/syscons/syscons.c
1.87 +17 -1 src/sys/dev/syscons/syscons.h
1.218 +1 -0 src/sys/kern/subr_witness.c
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