> -----Original Message----- > From: andrescj via sendgmr <andrescj@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> > On Behalf Of Andres Calderon Jaramillo > Sent: Tuesday, December 15, 2020 3:50 AM > To: intel-gfx@xxxxxxxxxxxxxxxxxxxxx > Cc: Shankar, Uma <uma.shankar@xxxxxxxxx>; Venkatesh Reddy, Sushma > <sushma.venkatesh.reddy@xxxxxxxxx>; seanpaul@xxxxxxxxxxxx; Andres > Calderon Jaramillo <andrescj@xxxxxxxxxxxx> > Subject: [PATCH] drm/i915/display: Prevent double YUV range correction on HDR > planes > > From: Andres Calderon Jaramillo <andrescj@xxxxxxxxxxxx> > > Prevent the ICL HDR plane pipeline from performing YUV color range correction > twice when the input is in limited range. > > Before this patch the following could happen: user space gives us a YUV buffer in > limited range; per the pipeline in [1], the plane would first go through a "YUV > Range correct" stage that expands the range; the plane would then go through > the "Input CSC" stage which would also expand the range because > icl_program_input_csc() would use a matrix and an offset that assume limited- > range input; this would ultimately cause dark and light colors to appear darker > and lighter than they should respectively. > > This is an issue because if a buffer switches between being scanned out and > being composited with the GPU, the user will see a color difference. > If this switching happens quickly and frequently, the user will perceive this as a > flickering. > > [1] https://01.org/sites/default/files/documentation/intel-gfx-prm-osrc-icllp- > vol12-displayengine_0.pdf#page=281 Change looks good to me, double conversion should not be done. Plane input csc coefficients take care of the limited range. Reviewed-by: Uma Shankar <uma.shankar@xxxxxxxxx> > Signed-off-by: Andres Calderon Jaramillo <andrescj@xxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/display/intel_display.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_display.c > b/drivers/gpu/drm/i915/display/intel_display.c > index 761be8deaa9b..aeea344b06ad 100644 > --- a/drivers/gpu/drm/i915/display/intel_display.c > +++ b/drivers/gpu/drm/i915/display/intel_display.c > @@ -4811,6 +4811,13 @@ u32 glk_plane_color_ctl(const struct intel_crtc_state > *crtc_state, > plane_color_ctl |= > PLANE_COLOR_YUV_RANGE_CORRECTION_DISABLE; > } else if (fb->format->is_yuv) { > plane_color_ctl |= PLANE_COLOR_INPUT_CSC_ENABLE; > + > + /* > + * Disable the YUV range correction stage because the input CSC > + * stage already takes care of range conversion by using separate > + * matrices and offsets depending on the color range. > + */ > + plane_color_ctl |= > PLANE_COLOR_YUV_RANGE_CORRECTION_DISABLE; > } > > return plane_color_ctl; > -- > 2.29.2.684.gfbc64c5ab5-goog _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
