At Mon, 3 Nov 2008 00:30:28 +0100, Zoltan Devai wrote: > > Hi, > > There've been reports [1] about the sysem bell causing a hard lockup. > My machine was affected as well: Any speaker output hung the machine > completely, nothing in the logs, no magic sysrq, etc., looked like a > hardware problem. > Had a closer look on the issue, and it turned out that the pcspkr module is > responsible. The cause is the bad setup of Timer 2 in the i8253 controller, > which probably hangs the whole PIT controller. > > Intel datasheets [2] state that the timer registers are in an undefined > state after reset and they need to be programmed before enabling the > timer. (And enabling without programming the frequency first doesn't > make sense anyway). > > I don't know which chipsets are affected (if not all), it also depends on > the BIOS whether it initializes the timer (e.g. to beep when you start the > machine). > > The following patch solved the issue on my ICH6 notebook, couldn't > test it with any others, but should be safe to apply. > > I've also sent a patch to the linux-input list for the pcspkr module. > > [1] > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/146151 > https://bugs.launchpad.net/ubuntu/+bug/270790 > http://ubuntuforums.org/showthread.php?t=227693 > http://bugs.gentoo.org/show_bug.cgi?id=222583 > https://bugzilla.redhat.com/show_bug.cgi?id=454225 > > [2] > http://www.intel.com/assets/pdf/datasheet/252516.pdf > http://www.intel.com/assets/pdf/datasheet/301473.pdf > http://www.intel.com/design/chipsets/datashts/29065503.pdf > > ------------------ > > Fix PIT lockup on some chipsets when using the PC-Speaker. > > Signed-off-by: Zoltan Devai <zdevai@xxxxxxxxx> Looks good to me. Applied now. Thanks! Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
