>From 3d0b1a15302aa704c7cf4ebbf7c2b8a1566b9beb Mon Sep 17 00:00:00 2001 From: Thomas Richter Date: Sat, 28 Mar 2015 10:57:46 +0100 Subject: [PATCH 1/1] Enabled dithering in the intel VCH DVO for 18bpp pipelines. Signed-off-by: Thomas Richter --- drivers/gpu/drm/i915/dvo_ivch.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-) 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 * + * Minor modifications (Dithering enable): + * Thomas Richter + * */ #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 @@ static void ivch_mode_set(struct intel_dvo_device *dvo, struct drm_display_mode *adjusted_mode) { uint16_t vr40 = 0; - uint16_t vr01; + uint16_t vr01 = 0; + uint16_t vr10; + + 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; - vr01 = 0; vr40 = (VR40_STALL_ENABLE | VR40_VERTICAL_INTERP_ENABLE | VR40_HORIZONTAL_INTERP_ENABLE); @@ -353,7 +366,7 @@ static void ivch_mode_set(struct intel_dvo_device *dvo, 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 @@ static void ivch_dump_regs(struct intel_dvo_device *dvo) 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); -- 1.7.10.4