Re: regression/bisected/6.7rc1: Instead of desktop I see a horizontal flashing bar with a picture of the desktop background on white screen

[Alex Deucher]

On Mon, Dec 18, 2023 at 1:31 PM Mikhail Gavrilov
<mikhail.v.gavrilov@xxxxxxxxx> wrote:
>
> On Fri, Dec 15, 2023 at 9:14 PM Hamza Mahfooz <hamza.mahfooz@xxxxxxx> wrote:
> >
> > Can you try the following patch with old fw (version 0x07002100 should
> > be fine)?: https://patchwork.freedesktop.org/patch/572298/
> >
>
> Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@xxxxxxxxx> on 7900XTX hardware.
>
> Can I ask?
> What does SubVP actually do?
> I read on Phoronix that this is new feature of DCN 3.2 hardware
> https://www.phoronix.com/news/AMDGPU-Linux-6.5-Improvements
> But I didn't notice that anything began to work better after enabling
> this feature.
> On the contrary, my kernel logs began to become overgrown with
> unpleasant errors.
> See here: https://gitlab.freedesktop.org/drm/amd/-/issues/2796
> I bisected this issue and bisect heads me to commit
> 299004271cbf0315da327c4bd67aec3e7041cb32 which enables SubVP high
> refresh rate.
> But without SubVP I also had 120Hz and 4K. So I ask again what is the
> profit of SubVP?

IIRC, SubVP is a power saving feature which allows us to dynamically
adjust the memory clocks in more cases with narrow blanking periods.

Alex