Re: next-20130709 DMAR issues

From: Valdis . Kletnieks
Date: Tue Jul 16 2013 - 18:08:45 EST


On Fri, 12 Jul 2013 14:14:20 +0200, Ingo Molnar said:
>
> (Cc:-ed a few DMAR people.)

Sorry for the slow reply, missed this in the lkml firehose.

For whatever reason, the damned problem seems to have evaporated:

% egrep -i 'dmar|Linux vers' /var/log/messages-20130714
....
Jul 11 18:54:15 turing-police kernel: [ 0.000000] Linux version 3.10.0-next-20130709 (valdis@xxxxxxxxxxxxxxxxxxxxxxx) (gcc version 4.8.1 20130612 (Red Hat 4.8.1-2) (GCC) ) #100 SMP PREEMPT Tue Jul 9 16:01:59 EDT 2013
Jul 11 18:54:15 turing-police kernel: [ 0.000000] ACPI: DMAR 00000000cb7fd298 00080 (v01 INTEL SNB 00000001 INTL 00000001)
Jul 11 18:54:15 turing-police kernel: [ 0.021632] dmar: Host address width 36
Jul 11 18:54:15 turing-police kernel: [ 0.021638] dmar: DRHD base: 0x000000fed90000 flags: 0x1
Jul 11 18:54:15 turing-police kernel: [ 0.021669] dmar: IOMMU 0: reg_base_addr fed90000 ver 1:0 cap c9008020660262 ecap f0105a
Jul 11 18:54:15 turing-police kernel: [ 0.021677] dmar: RMRR base: 0x000000ce761000 end: 0x000000ce780fff
Jul 11 18:54:15 turing-police kernel: [ 0.021775] dmar: DRHD: handling fault status reg 2
Jul 11 18:54:15 turing-police kernel: [ 0.021782] dmar: DMAR:[DMA Read] Request device [00:1f.2] fault addr ce71d000
Jul 11 18:54:15 turing-police kernel: [ 0.021782] DMAR:[fault reason 06] PTE Read access is not set
Jul 11 18:54:15 turing-police kernel: [ 1.002171] DMAR: No ATSR found
Jul 11 22:12:39 turing-police kernel: [ 0.000000] Linux version 3.10.0-next-20130709 (valdis@xxxxxxxxxxxxxxxxxxxxxxx) (gcc version 4.8.1 20130612 (Red Hat 4.8.1-2) (GCC) ) #100 SMP PREEMPT Tue Jul 9 16:01:59 EDT 2013
Jul 11 22:12:39 turing-police kernel: [ 0.000000] ACPI: DMAR 00000000cb7fd298 00080 (v01 INTEL SNB 00000001 INTL 00000001)
Jul 11 22:12:39 turing-police kernel: [ 0.021376] dmar: Host address width 36
Jul 11 22:12:39 turing-police kernel: [ 0.021382] dmar: DRHD base: 0x000000fed90000 flags: 0x1
Jul 11 22:12:39 turing-police kernel: [ 0.021414] dmar: IOMMU 0: reg_base_addr fed90000 ver 1:0 cap c9008020660262 ecap f0105a
Jul 11 22:12:39 turing-police kernel: [ 0.021422] dmar: RMRR base: 0x000000ce761000 end: 0x000000ce780fff
Jul 11 22:12:39 turing-police kernel: [ 1.034107] DMAR: No ATSR found

Damned if I know what changed - same kernel booted at 18:54 hit the issue, but
at 22:12 it had gone into hiding, and I haven't seen it since. (And the
laptop gets booted twice a day most days - once at arrival at office, and
once when I get home, and it had been doing it consistently at both locations
for several days.)

Definitely well into "things that go bump in the night" category.

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