Re: radeon KMS causes GART Table Walk Errors (was: K8 ECC error with linux-2.6.32)

From: Johannes Hirte
Date: Wed Dec 16 2009 - 14:31:59 EST


Am Mittwoch 16 Dezember 2009 19:41:48 schrieb Jerome Glisse:
> On Wed, Dec 16, 2009 at 03:58:30PM +0100, Johannes Hirte wrote:
> > Am Mittwoch 16 Dezember 2009 08:14:43 schrieb Borislav Petkov:
> > > On Tue, Dec 15, 2009 at 11:00:46PM +0100, Johannes Hirte wrote:
> > > > This patch (as the BIOS option) will only disable the error reports.
> > > > The error itself will still occur, right? So necessary to find out
> > > > why the radeon driver trigger this error.
> > >
> > > Because the graphics driver does aperture accesses with no
> > > matching GART translation, and the hw generates mchecks for
> > > that. The whole story on GART table walk errors is in section
> > > "13.10.1 GART Table Walk Error Reporting" in the document here:
> > > http://support.amd.com/us/Processor_TechDocs/32559.pdf
> > >
> > > I can't say for sure about your BIOS, but if it is done as described in
> > > the abovementioned section, the BIOS option should disable logging of
> > > the error, which implies reporting too.
> > >
> > > The patch is still needed for machines that do not have that BIOS
> > > option.
> >
> > Disabling in BIOS doesn't made any difference. The errors were still
> > reported. Your patch disabled it. But I think this will make work harder
> > for driver developers as they won't get this error anymore. Could this be
> > made changeable on runtime/boottime?
> >
> > I've added drm people to CC as they're responsible for this error.
> >
> >
> > regards,
> > Johannes
>
> More context would be usefull. Are you using KMS ? If so is your userspace
> KMS capable ? Does this GART error happen all the time or only after
> sometimes or when doing somethings specific ?

Yes I'm using KMS when this error occours.
Hardware:
- Tyan Tiger K8W S8875 (AMD8151 Northbridge)
- Radeon HD3650 AGP (RV635)

Software:
- linux-2.6.32
- libdrm-2.4.16
- mesa-7.7_rc2
- xf86-video-ati-9999 (latest git everytime)
- KDE-4.3.4 with compositing enabled (OpenGL)

The errors occours after a while of normal desktop work. I haven't tested
without KMS or compisiting. Will do this as well.

regards,
Johannes



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