Enabled dithering in the intel VCH DVO for 18bpp pipelines.
Signed-off-by: Thomas Richter <thor@math.tu-berlin.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/dvo_ivch.c b/drivers/gpu/drm/i915/dvo_ivch.c
index 0f2587f..89b08a8 100644
--- a/drivers/gpu/drm/i915/dvo_ivch.c
+++ b/drivers/gpu/drm/i915/dvo_ivch.c
@@ -23,6 +23,9 @@
* Authors:
* Eric Anholt <eric@anholt.net>
*
+ * Minor modifications (Dithering enable):
+ * Thomas Richter <thor@math.tu-berlin.de>
+ *
*/
#include "dvo.h"
@@ -59,6 +62,8 @@
# define VR01_DVO_BYPASS_ENABLE (1 << 1)
/** Enables the DVO clock */
# define VR01_DVO_ENABLE (1 << 0)
+/** Enable dithering for 18bpp panels. Not documented. */
+# define VR01_DITHER_ENABLE (1 << 4)
/*
* LCD Interface Format
@@ -74,6 +79,8 @@
# define VR10_INTERFACE_2X18 (2 << 2)
/** Enables 2x24-bit LVDS output */
# define VR10_INTERFACE_2X24 (3 << 2)
+/** Mask that defines the depth of the pipeline */
+# define VR10_INTERFACE_DEPTH_MASK (3 << 2)
/*
* VR20 LCD Horizontal Display Size
@@ -342,9 +349,15 @@
struct drm_display_mode *adjusted_mode)
{
uint16_t vr40 = 0;
- uint16_t vr01;
+ uint16_t vr01 = 0;
+ uint16_t vr10;
- vr01 = 0;
+ ivch_read(dvo, VR10, &vr10);
+ /* Enable dithering for 18 bpp pipelines */
+ vr10 &= VR10_INTERFACE_DEPTH_MASK;
+ if (vr10 == VR10_INTERFACE_2X18 || vr10 == VR10_INTERFACE_1X18)
+ vr01 = VR01_DITHER_ENABLE;
+
vr40 = (VR40_STALL_ENABLE | VR40_VERTICAL_INTERP_ENABLE |
VR40_HORIZONTAL_INTERP_ENABLE);
@@ -353,7 +366,7 @@
uint16_t x_ratio, y_ratio;
vr01 |= VR01_PANEL_FIT_ENABLE;
- vr40 |= VR40_CLOCK_GATING_ENABLE;
+ vr40 |= VR40_CLOCK_GATING_ENABLE | VR40_ENHANCED_PANEL_FITTING;
x_ratio = (((mode->hdisplay - 1) << 16) /
(adjusted_mode->hdisplay - 1)) >> 2;
y_ratio = (((mode->vdisplay - 1) << 16) /
@@ -380,6 +393,8 @@
DRM_DEBUG_KMS("VR00: 0x%04x\n", val);
ivch_read(dvo, VR01, &val);
DRM_DEBUG_KMS("VR01: 0x%04x\n", val);
+ ivch_read(dvo, VR10, &val);
+ DRM_DEBUG_KMS("VR10: 0x%04x\n", val);
ivch_read(dvo, VR30, &val);
DRM_DEBUG_KMS("VR30: 0x%04x\n", val);
ivch_read(dvo, VR40, &val);