Re: [PATCH v4 2/2] drm/mediatek: dpi/dsi: fix possible_crtcs calculation

[Michael Walle]

Hi,

> > > mtk_drm_find_possible_crtc_by_comp() assumed that the main path will
> > > always have the CRTC with id 0, the ext id 1 and the third id 2. This
> > > is only true if the paths are all available. But paths are optional
> > > (see
> > > also comment in mtk_drm_kms_init()), e.g. the main path might not be
> > > enabled or available at all. Then the CRTC IDs will shift one up, e.g.
> > > ext will be 0 and the third path will be 1.
> > >
> > > To fix that, dynamically calculate the IDs by the presence of the
> > > paths.
> > >
> > > While at it, make the return code a signed one and return -ENOENT if no
> > > path is found and handle the error in the callers.
> > >
> > > Fixes: 5aa8e7647676 ("drm/mediatek: dpi/dsi: Change the getting
> > > possible_crtc way")
> > > Suggested-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx>
> > > Signed-off-by: Michael Walle <mwalle@xxxxxxxxxx>
> > > Reviewed-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx>
> > > Tested-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx>
> >
> > Is there anything wrong with these two patches? They are now lingering
> > around for more than two months.
> >
> > Unfortunately, patch 2/2 won't apply anymore because of commit
> > 01389b324c97 ("drm/mediatek: Add connector dynamic selection
> > capability). And I'm a bit puzzled for what the crtc_id is used
> > there because I guess it will have the same problem this patch
> > fixes.
>
> Please base on the latest kernel version to fix.

Of course, but the question is how to fix it. Maybe Jason-JH.Lin
can help here.

In any case, please pick patch 1/2, it's independent of the second
patch and should still apply.

-michael