[BUG 4.17] etnaviv-gpu f1840000.gpu: recover hung GPU!

[Lucas Stach]

Hi Russell,

Am Dienstag, den 26.06.2018, 16:36 +0100 schrieb Russell King - ARM
Linux:
> On Tue, Jun 26, 2018 at 09:17:26AM +0100, Russell King - ARM Linux
> wrote:
> > On Tue, Jun 19, 2018 at 02:28:46PM +0200, Lucas Stach wrote:
> > > Agreed. I'll look into bringing back the process detection for
> > > 4.17
> > > stable.
> > > 
> > > I'm still curious why the GC600 on the Dove is that slow. With
> > > performance like this moving a big(ish) window on the screen must
> > > be a
> > > horrible user experience.
> > 
> > This doesn't seem to be the cause - it seems that there's something
> > going on with 4.17 that really is causing the Dove GC600 to get
> > stuck.
> > Reverting all the drivers/gpu/drm/etnaviv changes back to the 4.16
> > state while keeping everything else the same results in no hangs,
> > whereas increasing the timeout with 4.17 still results in hangs.
> > 
> > I'll try to find some time to bisect.
> 
> Sorry, it seems that my attempts to change what was running on the
> system were ineffective (due to the etnaviv module loaded from the
> initramfs, not from the fs copy I was updating.)  Extending the
> timeout to 5 seconds does indeed stop the issue.

Thanks for confirming that the issue is caused by the removed progress
check.

> More importantly, it stops some memory corruption I've observed as
> well, caused by etnaviv freeing buffers when it thinks the GPU has
> timed out while the GPU is still writing to them.

Urgh, that is really bad. I'll get a fix out of the door tomorrow.

Regards,
Lucas