[PATCH 1/3] drm/radeon: stop poisoning the GART TLB

[Marek Olšák]

Hi Michel,

3.15 doesn't contain Christian's fix yet, so it should be always
broken for everybody. The fix is currently only in 3.16.

Alternatively, you can cherry-pick the fix to 3.15, but it doesn't
apply cleanly.

There is a workaround in 3.15 which disables sDMA and uses CP DMA for
copying buffers. It seems to help Christian's machine, but not mine.

When I said the kernel driver was broken, I meant that
it was broken *with* the fix applied regardless of which engine was
used for the copying.

Marek

On Thu, Jun 19, 2014 at 3:48 AM, Michel Dänzer <michel at daenzer.net> wrote:
> On 15.06.2014 21:48, Christian König wrote:
>> Am 13.06.2014 23:31, schrieb Alex Deucher:
>>> On Fri, Jun 13, 2014 at 11:45 AM, Christian König
>>> <deathsimple at vodafone.de> wrote:
>>>> Hi Marek,
>>>>
>>>> ah, yes! Piglit in combination with that patch can indeed crash the box.
>>>>
>>>> Going to investigate now that I can reproduce it.
>>> I wonder if it's a clockgating issue with the MC or BIF?  You might
>>> try adjusting the rdev->cg_flags (try setting it to 0) in
>>> radeon_asic.c or disabling dpm.
>>
>> Unfortunately that was just a false alarm.
>>
>> I was just on a branch which didn't had the "stop poisoning the GART
>> TLB" patch, after applying this patch I can again let piglit run for the
>> whole night without a lockup.
>>
>> No idea what goes wrong when Marek runs piglit, but 3.15.0+"stop
>> poisoning the GART TLB"+"force_gtt" is rock solid here.
>
> FWIW, 3.15 doesn't survive piglit on my Bonaire either, but 3.14 is
> fine. 3.15 seems stable on Kaveri though, but I haven't tried the
> force_gtt patch on that yet.
>
> There have also been a number of bug reports about stability regressions
> in 3.15 on various SI and CIK cards. It seems likely that at least some
> of those are related to this issue as well.
>
> If we can't figure out the problem soon, we probably need to revert the
> 'Use normal BOs for page tables' and dependent changes at least for 3.15.y?
>
>
> --
> Earthling Michel Dänzer            |                  http://www.amd.com
> Libre software enthusiast          |                Mesa and X developer
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