Date: Wed, 10 Jun 2015 01:09:43 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 200748] Issues after resume when TSC timecounter selected, possibly due to CPU TSC resetting to zero Message-ID: <bug-200748-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=200748 Bug ID: 200748 Summary: Issues after resume when TSC timecounter selected, possibly due to CPU TSC resetting to zero Product: Base System Version: 11.0-CURRENT Hardware: Any OS: Any Status: New Severity: Affects Only Me Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: gavin@FreeBSD.org Created attachment 157592 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=157592&action=edit Verbose dmesg I have a Lenovo Flex 10 laptop. With kern.timecounter.hardware=TSC (the default), on resume there are serious issues: primarily that time appears to run very fast, the AHCI controller/drive fail to reinit correctly, etc. Unfortunately the video doesn't recover either (unrelated to this issue), so it's a bit hard to establish exactly what state the machine is in at this time. After some digging, it looks like the CPU TSC counter is reset to zero on resume: root@flex10:~ # cpucontrol -m 0x10 /dev/cpuctl0 ; cpucontrol -m 0x10 /dev/cpuctl1 MSR 0x10: 0x0000019a 0x3d2660a7 MSR 0x10: 0x0000019a 0x5f4b9d7a root@flex10:~ # zzz [wake machine up] root@flex10:~ # cpucontrol -m 0x10 /dev/cpuctl0 ; cpucontrol -m 0x10 /dev/cpuctl1 MSR 0x10: 0x00000004 0x27c4514f MSR 0x10: 0x00000004 0x49dcc993 I suspect (though haven't been able to prove) that this is the cause. The CPU is an Intel N2807 ultra low power CPU. It does have invariant P state TSC. -- You are receiving this mail because: You are the assignee for the bug.
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