Messages in this thread | | | Date | Mon, 10 Jul 2006 01:53:09 +0200 (MEST) | From | Mikael Pettersson <> | Subject | Re: [BUG] APM resume breakage from 2.6.18-rc1 clocksource changes |
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On Sun, 09 Jul 2006 17:31:39 -0400, Valdis.Kletnieks wrote: >On Sun, 09 Jul 2006 22:58:31 +0200, Mikael Pettersson said: > >> I've traced the cause of this problem to the i386 time-keeping >> changes in kernel 2.6.17-git11. What happens is that: >> - The kernel autoselects TSC as my clocksource, which is >> reasonable since it's a PentiumII. 2.6.17 also chose the TSC. >> - Immediately after APM resumes (arch/i386/kernel/apm.c line >> 1231 in 2.6.18-rc1) there is an interrupt from the PIT, >> which takes us to kernel/timer.c:update_wall_time(). >> - update_wall_time() does a clocksource_read() and computes >> the offset from the previous read. However, the TSC was >> reset by HW or BIOS during the APM suspend/resume cycle and >> is now smaller than it was at the prevous read. On my machine, >> the offset is 0xffffffd598e0a566 at this point, which appears >> to throw update_wall_time() into a very very long loop. > >Does applying this patch make it work? > >ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.18-rc1/2.6.18-rc1-mm1/broken-out/adjust-clock-for-lost-ticks.patch > >Or is this a different breakage?
I haven't tried it, but I'm 99% certain it's unrelated breakage. In my case the TSC jumped backwards not forwards as would be the case in a lost ticks scenario, and the patch above doesn't touch the code that gets into an semi-infinite loop in my case.
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