[AMD Official Use Only - AMD Internal Distribution Only] Hi Tomi
> -----Original Message----- > From: Tomi Valkeinen <[email protected]> > Sent: Wednesday, December 18, 2024 12:49 PM > To: Sagar, Vishal <[email protected]> > Cc: [email protected]; [email protected]; linux-arm- > [email protected]; Klymenko, Anatoliy <[email protected]>; > Maarten Lankhorst <[email protected]>; Maxime Ripard > <[email protected]>; Thomas Zimmermann <[email protected]>; David > Airlie <[email protected]>; Simona Vetter <[email protected]>; Laurent Pinchart > <[email protected]>; Simek, Michal <[email protected]> > Subject: Re: [PATCH 01/10] drm/fourcc: Add warning for bad bpp > > Hi Vishal, > > On 04/12/2024 18:26, Sagar, Vishal wrote: > > [AMD Official Use Only - AMD Internal Distribution Only] > > > > Hi Tomi, > > > > Thanks for the patch. > > > >> -----Original Message----- > >> From: Tomi Valkeinen <[email protected]> > >> Sent: Wednesday, December 4, 2024 10:31 AM > >> To: Sagar, Vishal <[email protected]>; Klymenko, Anatoliy > >> <[email protected]>; Maarten Lankhorst > >> <[email protected]>; Maxime Ripard <[email protected]>; > >> Thomas Zimmermann <[email protected]>; David Airlie > >> <[email protected]>; Simona Vetter <[email protected]>; Laurent Pinchart > >> <[email protected]>; Simek, Michal > <[email protected]> > >> Cc: [email protected]; [email protected]; > >> linux-arm- > >> [email protected]; Tomi Valkeinen > <[email protected]> > >> Subject: [PATCH 01/10] drm/fourcc: Add warning for bad bpp > >> > >> drm_format_info_bpp() cannot be used for formats which do not have an > >> integer bits-per-pixel. Handle wrong calls by printing a warning and > >> returning 0. > > > > It would be good to add an example of pixel format that may cause this > > issue. > > Indeed, the description is perhaps a bit lacking. I'll change it to: > > drm_format_info_bpp() cannot be used for formats which do not have an > integer bits-per-pixel in a pixel block. > > E.g. DRM_FORMAT_XV15's (not yet in upstream) plane 0 has three 10-bit > pixels (Y components), and two padding bits, in a 4 byte block. That is > 10.666... bits per pixel when considering the whole 4 byte block, which > is what drm_format_info_bpp() does. Thus a driver that supports such > formats cannot use drm_format_info_bpp(), > > It is a driver bug if this happens, but so handle wrong calls by > printing a warning and returning 0. > This looks good to me. Vishal > Tomi > > >> > >> Signed-off-by: Tomi Valkeinen <[email protected]> > >> --- > >> drivers/gpu/drm/drm_fourcc.c | 7 +++++++ > >> 1 file changed, 7 insertions(+) > >> > >> diff --git a/drivers/gpu/drm/drm_fourcc.c b/drivers/gpu/drm/drm_fourcc.c > >> index 193cf8ed7912..e84c4ed6928c 100644 > >> --- a/drivers/gpu/drm/drm_fourcc.c > >> +++ b/drivers/gpu/drm/drm_fourcc.c > >> @@ -429,6 +429,13 @@ unsigned int drm_format_info_bpp(const struct > >> drm_format_info *info, int plane) > >> if (!info || plane < 0 || plane >= info->num_planes) > >> return 0; > >> > >> + if (info->char_per_block[plane] * 8 % > >> + (drm_format_info_block_width(info, plane) * > >> + drm_format_info_block_height(info, plane))) { > >> + pr_warn("unable to return an integer bpp\n"); > >> + return 0; > >> + } > >> + > >> return info->char_per_block[plane] * 8 / > >> (drm_format_info_block_width(info, plane) * > >> drm_format_info_block_height(info, plane)); > >> > >> -- > >> 2.43.0 > > > > Regards > > Vishal Sagar
