Up to now we've relied on the bios to get this right for us. Let's try
out whether our code has improved a bit, since we should dither
always when the output bpp doesn't match the plane bpp.
- gen5+ should be fine, since we only use the bios hint as an upgrade.
- gen4 changes, since here dithering is still controlled in the lvds
register.
- gen2/3 has implicit dithering depeding upon whether you use 2 or 3
lvds pairs (which makes sense, since it only supports 8bpc pipe
outpu configurations).
- hsw doesn't support lvds.
v2: Remove redudant dither setting.
v3: Completly drop reliance on dev_priv->lvds_dither.
v4: Enable dithering on gen2/3 only when we have a 18bpp panel, since
up-dithering to a 24bpp panel is not supported by the hw. Spotted by
Ville.
v5: Also only enable lvds port dithering on gen4 for 18bpp modes. In
practice this only excludes dithering a 10bpc plane down for a 24bpp
lvds panel. Not something we truly care about. Again noticed by Ville.
v6: Actually git add.
Cc: Ville Syrj?l? <ville.syrjala at linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
drivers/gpu/drm/i915/intel_display.c | 25 +++++++------------------
drivers/gpu/drm/i915/intel_drv.h | 5 +++++
drivers/gpu/drm/i915/intel_lvds.c | 15 ++++++++++-----
3 files changed, 22 insertions(+), 23 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 16106fe..f26a867 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5156,8 +5156,7 @@ static int ironlake_get_refclk(struct drm_crtc *crtc)
}
static void ironlake_set_pipeconf(struct drm_crtc *crtc,
- struct drm_display_mode *adjusted_mode,
- bool dither)
+ struct drm_display_mode *adjusted_mode)
{
struct drm_i915_private *dev_priv = crtc->dev->dev_private;
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
@@ -5186,7 +5185,7 @@ static void ironlake_set_pipeconf(struct drm_crtc *crtc,
}
val &= ~(PIPECONF_DITHER_EN | PIPECONF_DITHER_TYPE_MASK);
- if (dither)
+ if (intel_crtc->config.dither)
val |= (PIPECONF_DITHER_EN | PIPECONF_DITHER_TYPE_SP);
val &= ~PIPECONF_INTERLACE_MASK;
@@ -5269,8 +5268,7 @@ static void intel_set_pipe_csc(struct drm_crtc *crtc)
}
static void haswell_set_pipeconf(struct drm_crtc *crtc,
- struct drm_display_mode *adjusted_mode,
- bool dither)
+ struct drm_display_mode *adjusted_mode)
{
struct drm_i915_private *dev_priv = crtc->dev->dev_private;
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
@@ -5280,7 +5278,7 @@ static void haswell_set_pipeconf(struct drm_crtc *crtc,
val = I915_READ(PIPECONF(cpu_transcoder));
val &= ~(PIPECONF_DITHER_EN | PIPECONF_DITHER_TYPE_MASK);
- if (dither)
+ if (intel_crtc->config.dither)
val |= (PIPECONF_DITHER_EN | PIPECONF_DITHER_TYPE_SP);
val &= ~PIPECONF_INTERLACE_MASK_HSW;
@@ -5641,7 +5639,7 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
bool is_lvds = false;
struct intel_encoder *encoder;
int ret;
- bool dither, fdi_config_ok;
+ bool fdi_config_ok;
for_each_encoder_on_crtc(dev, crtc, encoder) {
switch (encoder->type) {
@@ -5676,11 +5674,6 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
/* Ensure that the cursor is valid for the new mode before changing... */
intel_crtc_update_cursor(crtc, true);
- /* determine panel color depth */
- dither = intel_crtc->config.dither;
- if (is_lvds && dev_priv->lvds_dither)
- dither = true;
-
DRM_DEBUG_KMS("Mode for pipe %c:\n", pipe_name(pipe));
drm_mode_debug_printmodeline(mode);
@@ -5747,7 +5740,7 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
fdi_config_ok = ironlake_check_fdi_lanes(intel_crtc);
- ironlake_set_pipeconf(crtc, adjusted_mode, dither);
+ ironlake_set_pipeconf(crtc, adjusted_mode);
/* Set up the display plane register */
I915_WRITE(DSPCNTR(plane), DISPPLANE_GAMMA_ENABLE);
@@ -5824,7 +5817,6 @@ static int haswell_crtc_mode_set(struct drm_crtc *crtc,
bool is_cpu_edp = false;
struct intel_encoder *encoder;
int ret;
- bool dither;
for_each_encoder_on_crtc(dev, crtc, encoder) {
switch (encoder->type) {
@@ -5860,9 +5852,6 @@ static int haswell_crtc_mode_set(struct drm_crtc *crtc,
/* Ensure that the cursor is valid for the new mode before changing... */
intel_crtc_update_cursor(crtc, true);
- /* determine panel color depth */
- dither = intel_crtc->config.dither;
-
DRM_DEBUG_KMS("Mode for pipe %c:\n", pipe_name(pipe));
drm_mode_debug_printmodeline(mode);
@@ -5876,7 +5865,7 @@ static int haswell_crtc_mode_set(struct drm_crtc *crtc,
if (intel_crtc->config.has_pch_encoder)
ironlake_fdi_set_m_n(crtc);
- haswell_set_pipeconf(crtc, adjusted_mode, dither);
+ haswell_set_pipeconf(crtc, adjusted_mode);
intel_set_pipe_csc(crtc);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 66922f8..723cac9 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -213,6 +213,11 @@ struct intel_crtc_config {
/* DP has a bunch of special case unfortunately, so mark the pipe
* accordingly. */
bool has_dp_encoder;
+
+ /*
+ * Enable dithering, used when the selected pipe bpp doesn't match the
+ * plane bpp.
+ */
bool dither;
/* Controls for the clock computation, to override various stages. */
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 563f505..8408545 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -136,7 +136,10 @@ static void intel_pre_pll_enable_lvds(struct intel_encoder *encoder)
* special lvds dither control bit on pch-split platforms, dithering is
* only controlled through the PIPECONF reg. */
if (INTEL_INFO(dev)->gen == 4) {
- if (dev_priv->lvds_dither)
+ /* Bspec wording suggests that LVDS port dithering only exists
+ * for 18bpp panels. */
+ if (intel_crtc->config.dither &&
+ intel_crtc->config.pipe_bpp == 18)
temp |= LVDS_ENABLE_DITHER;
else
temp &= ~LVDS_ENABLE_DITHER;
@@ -335,7 +338,13 @@ static bool intel_lvds_compute_config(struct intel_encoder *intel_encoder,
DRM_DEBUG_KMS("forcing display bpp (was %d) to LVDS (%d)\n",
pipe_config->pipe_bpp, lvds_bpp);
pipe_config->pipe_bpp = lvds_bpp;
+
+ /* Make sure pre-965 set dither correctly for 18bpp panels. */
+ if (INTEL_INFO(dev)->gen < 4 && lvds_bpp == 18)
+ pfit_control |= PANEL_8TO6_DITHER_ENABLE;
+
}
+
/*
* We have timings from the BIOS for the panel, put them in
* to the adjusted mode. The CRTC will be set up for this mode,
@@ -470,10 +479,6 @@ out:
pfit_pgm_ratios = 0;
}
- /* Make sure pre-965 set dither correctly */
- if (INTEL_INFO(dev)->gen < 4 && dev_priv->lvds_dither)
- pfit_control |= PANEL_8TO6_DITHER_ENABLE;
-
if (pfit_control != lvds_encoder->pfit_control ||
pfit_pgm_ratios != lvds_encoder->pfit_pgm_ratios) {
lvds_encoder->pfit_control = pfit_control;
--
1.7.11.7
