[PATCH v2] drm/tiny: panel-mipi-dbi: Use drm_client_setup_with_fourcc()

[Fabio Estevam]

Hi Javier and Thomas,

On Tue, Apr 22, 2025 at 6:53 PM Javier Martinez Canillas
<javierm at redhat.com> wrote:
>
> Fabio Estevam <festevam at gmail.com> writes:
>
> Hello Fabio,
>
> > From: Fabio Estevam <festevam at denx.de>
> >
> > Since commit 559358282e5b ("drm/fb-helper: Don't use the preferred depth
> > for the BPP default"), RGB565 displays such as the CFAF240320X no longer
> > render correctly: colors are distorted and the content is shown twice
> > horizontally.
> >
> > This regression is due to the fbdev emulation layer defaulting to 32 bits
> > per pixel, whereas the display expects 16 bpp (RGB565). As a result, the
> > framebuffer data is incorrectly interpreted by the panel.
> >
> > Fix the issue by calling drm_client_setup_with_fourcc() with a format
> > explicitly selected based on the display's bits-per-pixel value. For 16
> > bpp, use DRM_FORMAT_RGB565; for other values, fall back to the previous
> > behavior. This ensures that the allocated framebuffer format matches the
> > hardware expectations, avoiding color and layout corruption.
> >
> > Tested on a CFAF240320X display with an RGB565 configuration, confirming
> > correct colors and layout after applying this patch.
> >
> > Cc: stable at vger.kernel.org
> > Fixes: 559358282e5b ("drm/fb-helper: Don't use the preferred depth for the BPP default")
> > Signed-off-by: Fabio Estevam <festevam at denx.de>
> > Reviewed-by: Thomas Zimmermann <tzimmermann at suse.de>
> > ---
>
> Reviewed-by: Javier Martinez Canillas <javierm at redhat.com>

Could you please help apply this fix?

Thanks