[PATCH 1/3] drm/vkms: Set preferred depth correctly

[Daniel Vetter]

On Tue, Oct 27, 2020 at 11:13 AM Thomas Zimmermann <tzimmermann at suse.de> wrote:
>
> Hi
>
> Am 16.10.20 um 13:35 schrieb Daniel Vetter:
> > On Fri, Oct 16, 2020 at 12:38 PM Simon Ser <contact at emersion.fr> wrote:
> >>
> >>> The only thing we support is xrgb8888.
> >>>
> >>> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> >>> Cc: Rodrigo Siqueira <rodrigosiqueiramelo at gmail.com>
> >>> Cc: Melissa Wen <melissa.srw at gmail.com>
> >>> Cc: Haneen Mohammed <hamohammed.sa at gmail.com>
> >>> Cc: Daniel Vetter <daniel at ffwll.ch>
> >>> ---
> >>>  drivers/gpu/drm/vkms/vkms_drv.c | 2 +-
> >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c
> >>> index 726801ab44d4..eb4007443706 100644
> >>> --- a/drivers/gpu/drm/vkms/vkms_drv.c
> >>> +++ b/drivers/gpu/drm/vkms/vkms_drv.c
> >>> @@ -124,7 +124,7 @@ static int vkms_modeset_init(struct vkms_device *vkmsdev)
> >>>       dev->mode_config.max_height = YRES_MAX;
> >>>       dev->mode_config.cursor_width = 512;
> >>>       dev->mode_config.cursor_height = 512;
> >>> -     dev->mode_config.preferred_depth = 24;
> >>> +     dev->mode_config.preferred_depth = 32;
> >>
> >> Are you sure xrgb8888's depth is 32 and not 24? Looking at drmdb [1], *all*
> >> drivers set it to 24.
> >
> > Uh there's a problem I think. Depth should indeed stay at 24, the
> > problem is that fb helpers directly take that to be the bpp parameter,
> > which is a different thing. And if you look at how most drivers set up
> > that, they pick 32.
> >
> > I guess I need to revert this here, and unconfuse the fb helpers about
> > depth vs bpp.
>
> I just prepared the PR for drm-misc-next, but saw it at 32 still. Was
> this supposed to be reverted?

Revert makes fbdev go boom, only thing that would work is leaving it
at 0 so that everyone picks the default. I've tried to come up with a
patch series to clean up this mess, but it's rather horrible :-/
-Daniel

>
> Best regards
> Thomas
>
> >
> > Maybe best would be to just switch over to preferred drm_fourcc format
> > code, or maybe just pick this up from the first format the primary
> > plane supports.
> >
> > This is all getting slightly tricky and a lot more work :-/
> > -Daniel
> > --
> > Daniel Vetter
> > Software Engineer, Intel Corporation
> > http://blog.ffwll.ch
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> >
>
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Maxfeldstr. 5, 90409 Nürnberg, Germany
> (HRB 36809, AG Nürnberg)
> Geschäftsführer: Felix Imendörffer



-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch