[Nouveau] [PATCH 1/2] Revert "bus: remove cpu_coherent flag"

[Martin Peres]

On 19/09/16 06:50, Alexandre Courbot wrote:
> On Mon, Sep 19, 2016 at 12:43 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
>> On Sun, Sep 18, 2016 at 11:39 PM, Alexandre Courbot <gnurou at gmail.com> wrote:
>>> On Sun, Sep 18, 2016 at 7:21 PM, Karol Herbst <karolherbst at gmail.com> wrote:
>>>> This reverts commit 01bbcb69f80e1058395b737ae399c6f4ef48691b.
>> I think you meant aff51175cdbf345740ec9203eff88e772af88059 - that's
>> the commit id that matters, not the one in Ben's non-linux repo.
>>
>>>> The commit caused fence timeouts within nvc0_screen_destroy and most likely
>>>> other places as well.
>>>>
>>>> The most obvious effect is, that userspace processes take minutes to actually
>>>> quit.
>>> Acked-by: Alexandre Courbot <acourbot at nvidia.com>
>> If this doesn't make it into v4.8 (which is due to be released in a
>> week), it should get tagged for stable as well.
>>
>> By the way, Alexandre, I believe Martin was reporting issues like this
>> on his TK1 before this change as well. Probably worth investigating -
>> sounds like there's a wider issue with TTM_PL_FLAG_UNCACHED and/or
>> force_coherent.
> Yes, it may be indeed related. I need to sync with Martin to
> understand his exact repro case.

Running piglit on the tk1 is enough for me, but I will try to update the 
kernel again to see if it helps.

The issue is that mesa is waiting on a fence that never gets synced on 
in the gbm destructor. The probably of having the timeout is about 
50/50, so it is easy-enough to reproduce in my case :s

Martin