Re: [PATCH] drm/msm/disp/dpu: consider SSPP line width during mode valid

[Vishnu Saini]

On Sun, Mar 29, 2026 at 02:24:53AM +0200, Dmitry Baryshkov wrote:
> On Sat, Mar 28, 2026 at 10:45:35PM +0530, Vishnu Saini wrote:
> > Few targets have lesser SSPP line width compared to mixer width,
> > SSPP line width also needs to be considered during mode valid
> > to avoid failures during atomic_check.
> 
> Technically this is not correct. There is no requirement for the
> planes to cover the whole CRTC. Nor is there a requirement to use only 2
> rectangles to cover the screen. As such, it is perfectly fine in
> mode_valid, if CRTC is wider than 2x max_linewidth. It would be an error
> if the user tries to stretch 2 rectangles in such a case.

This is to fix an issue with 5k monitor on rb3gen2, since SSPP maxlinewidth is 2400
it can't cover the whole 5k buffer in left right split mode.
Do we need to fix it from drm backend by dividing 5k buffer into 2 planes and 
use 2 pipes in split mode.
4 SSPP rects --> 2 LMs --> 3d_mux --> DP
 
> > 
> > Signed-off-by: Vishnu Saini <vishnu.saini@xxxxxxxxxxxxxxxx>
> > ---
> >  drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 12 ++++++++----
> >  1 file changed, 8 insertions(+), 4 deletions(-)
> > 
> 
> -- 
> With best wishes
> Dmitry