From 7cd015a0a37265e23bbdce7ce8f7e00507abe9ed Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Mon, 5 Sep 2011 11:53:21 -0700 Subject: [PATCH] drm/i915: Enable dither whenever display bpc < frame buffer bpc We want to enable dithering on any pipe where the frame buffer has more color resolution than the output device. The previous code was incorrectly clamping the frame buffer bpc to the display bpc, effectively disabling dithering all of the time as the computed frame buffer bpc would never be larger than the display bpc. Signed-off-by: Keith Packard Reported-by: Oliver Hartkopp Tested-by: Oliver Hartkopp --- drivers/gpu/drm/i915/intel_display.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 56a8554d9039..9fb4a40bd9e5 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -4687,13 +4687,13 @@ static bool intel_choose_pipe_bpp_dither(struct drm_crtc *crtc, bpc = 6; /* min is 18bpp */ break; case 24: - bpc = min((unsigned int)8, display_bpc); + bpc = 8; break; case 30: - bpc = min((unsigned int)10, display_bpc); + bpc = 10; break; case 48: - bpc = min((unsigned int)12, display_bpc); + bpc = 12; break; default: DRM_DEBUG("unsupported depth, assuming 24 bits\n"); @@ -4701,10 +4701,12 @@ static bool intel_choose_pipe_bpp_dither(struct drm_crtc *crtc, break; } + display_bpc = min(display_bpc, bpc); + DRM_DEBUG_DRIVER("setting pipe bpc to %d (max display bpc %d)\n", bpc, display_bpc); - *pipe_bpp = bpc * 3; + *pipe_bpp = display_bpc * 3; return display_bpc != bpc; } -- 2.30.2