Re: [PATCH v2 0/2] Fixes for omapdrm console

[Tony Lindgren <tony@atomide.com>]

* Thomas Zimmermann <tzimmermann@suse.de> [240226 09:10]:
> Hi
> 
> Am 26.02.24 um 10:01 schrieb Tomi Valkeinen:
> > On 26/02/2024 10:26, Tomi Valkeinen wrote:
> > > Hi Tony,
> > > 
> > > On 25/02/2024 08:46, Tony Lindgren wrote:
> > > > Here are two fixes for omapdrm console.
> > > 
> > > How is it broken? I don't usually use the console (or fbdev) but
> > > enabling it now, it seems to work fine for me, on DRA76 EVM with
> > > HDMI output.
> 
> Omapdrm implements drm_framebuffer_funcs.dirty withomap_framebuffer_dirty().
> AFAIK DRM semantics requires to run the dirty helper after writing to the
> framebuffer's memory. Userspace does this via the DIRTYFB ioctl. [1] But (at
> least) for correctness the console needs to do the same.
> 
> [1] https://elixir.bootlin.com/linux/v6.7.6/source/drivers/gpu/drm/drm_ioctl.c#L679

Yes I noticed console not updating and bisected it down to the two
commits listed. I did the bisect on a droid4 though with command mode
LCD. I did not test with HDMI, will give that a try too.

> > After applying your patches, I see a lot of cache-related artifacts on
> > the screen when updating the fb.
> 
> I guess we might need a dma-specific mmap helper to make this work
> correctly.

I can easily test this if you have some suggested patch to try.

Hmm so I wonder if we now have double updates happening on HDMI?

Regards,

Tony