bisected/regression: choopy youtube video on Ryzen IGP - 0ddd2ae586d2 drm/ttm: increase ttm pre-fault value to PMD size

[Yanko Kaneti]

Hi,

Well, it starts, then within a second or two it begins stuttering with
long (half a second/second) freezes of the video , while the audio seems
to work fine. Nothing in the log from chrome or kernel , AFAICS,  to
show anything is wrong.

Regards
Yanko

On Wed, 2024-07-24 at 09:02 +0200, Christian König wrote:
> Hi Yanko,
> 
> interesting. What do you mean with "choppy"? E.g. lag on startup?
> 
> Regards,
> Christian.
> 
> Am 23.07.24 um 21:42 schrieb Yanko Kaneti:
> > Hello,
> > 
> > Noticed and bisected a rawhide (with the new 6.11-rc0 snapshots) regression to this commit:
> > 
> >    0ddd2ae586d2 drm/ttm: increase ttm pre-fault value to PMD size
> > 
> > The regression manifests in choppy youtube video playback in google-chrome-stable.
> >   https://www.youtube.com/watch?v=uOpl2XNOgMA
> >   google-chrome-stable-126.0.6478.182-1.x86_64
> >   VP9 video,
> >   Chrome -> Override software rendering list -> on
> >   Chrome -> Hardware-accelerated video decode - default enabled
> > 
> > No other visible graphics issues.
> > 
> > Its a desktop system with Ryzen 7 5700GRyzen 7 5700G  IGP
> > [AMD/ATI] Cezanne [Radeon Vega Series / Radeon Vega Mobile Series] [1002:1638]
> > 
> > Tested with linus tip and just reverting the commit fixes the issue.
> > 
> > Sorry for the brevity, not sure what other details might be relevant.
> > 
> > - Yanko
> > 
> > 
>