diff mbox

drm/i915: Enable dither whenever display bpc < frame buffer bpc

Message ID 1315249215-13956-1-git-send-email-keithp@keithp.com
State New, archived
Headers show

Commit Message

Keith Packard Sept. 5, 2011, 7 p.m. UTC
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 <keithp@keithp.com>
Reported-by: Oliver Hartkopp <socketcan@hartkopp.net>
Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
---
 drivers/gpu/drm/i915/intel_display.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 56a8554..9fb4a40 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;
 }