linux-kernel - Re: [Intel-gfx] dmar messages caused by graphics.

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Date:	Tue, 21 Oct 2014 17:36:44 +0200
From:	Daniel Vetter <daniel@...ll.ch>
To:	Dave Jones <davej@...hat.com>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	intel-gfx@...ts.freedesktop.org, joro@...tes.org
Subject: Re: [Intel-gfx] dmar messages caused by graphics.

On Fri, Oct 17, 2014 at 05:17:16PM -0400, Dave Jones wrote:
> Just hit this while fuzz-testing, (curiously, no graphics
> related stuff was happening, X isn't even loaded on that box).
> 
> dmar: DRHD: handling fault status reg 2
> dmar: DMAR:[DMA Write] Request device [00:02.0] fault addr 7ffffff000
> DMAR:[fault reason 05] PTE Write access is not set
> 
> 
> 00:02:0 is..
> 
> 00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v3/4th
> Gen Core Processor Integrated Graphics Controller (rev 06) (prog-if 00
> 		[VGA controller])
> 
> 00: 86 80 12 04 07 04 90 00 06 00 00 03 00 00 00 00
> 10: 04 00 00 c0 00 00 00 00 0c 00 00 b0 00 00 00 00
> 20: 01 30 00 00 00 00 00 00 00 00 00 00 86 80 12 22
> 30: 00 00 00 00 90 00 00 00 00 00 00 00 0b 01 00 00
> 
> 
> So then I rebooted, and noticed it spewed the exact same message on boot up too.
> 
> I power cycled, and this time got
> 
> [    0.576231] dmar: Host address width 39
> [    0.576336] dmar: DRHD base: 0x000000fed90000 flags: 0x0
> [    0.576491] dmar: IOMMU 0: reg_base_addr fed90000 ver 1:0 cap c0000020660462 ecap f0101a
> [    0.576659] dmar: DRHD base: 0x000000fed91000 flags: 0x1
> [    0.576793] dmar: IOMMU 1: reg_base_addr fed91000 ver 1:0 cap d2008020660462 ecap f010da
> [    0.576961] dmar: RMRR base: 0x000000a2a1f000 end: 0x000000a2a32fff
> [    0.577075] dmar: RMRR base: 0x000000ad800000 end: 0x000000af9fffff
> [    6.715745] DMAR: No ATSR found
> [    8.081845] [drm] DMAR active, disabling use of stolen memory
> [    9.927343] dmar: DRHD: handling fault status reg 2
> [    9.928335] dmar: DMAR:[DMA Write] Request device [00:02.0] fault addr 3c11284000 
> DMAR:[fault reason 05] PTE Write access is not set
> [   11.916211] dmar: DRHD: handling fault status reg 2
> [   11.917105] dmar: DMAR:[DMA Write] Request device [00:02.0] fault addr 3c11284000 
> DMAR:[fault reason 05] PTE Write access is not set
> 
> 
> Same thing, different fault address.  It seems to change every time I boot.
> 
> 
> Looking in the logs, this started happening on the 15th. The first instance
> was this during boot..
> 
> [    9.917240] dmar: DRHD: handling fault status reg 2
> [    9.918150] dmar: DMAR:[DMA Write] Request device [00:02.0] fault addr 7300000000 
> [    9.918150] DMAR:[fault reason 05] PTE Write access is not set
> [    9.919582] dmar: DMAR:[DMA Write] Request device [00:02.0] fault addr 7ffffff000 
> [    9.919582] DMAR:[fault reason 05] PTE Write access is not set
> [   10.157240] dmar: DRHD: handling fault status reg 3
> [   10.158017] dmar: DMAR:[DMA Write] Request device [00:02.0] fault addr 3579736000 
> [   10.158017] DMAR:[fault reason 05] PTE Write access is not set
> [   11.926114] dmar: DRHD: handling fault status reg 3
> [   11.927117] dmar: DMAR:[DMA Write] Request device [00:02.0] fault addr 7300000000 
> [   11.927117] DMAR:[fault reason 05] PTE Write access is not set
> 
> That time, the 'reg 3' showed up.
> 
> Dying hardware ? Or bug ?

We see these occasionally after the gpu has gone bananas, and iirc also
sometimes after module reload (we probably botch the reinit stuff a bit).
That it happens without anything really going on from the gfx is slightly
more disturbing indeed. Any chance this could have been a kernel
regression?
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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