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authorDaniel Vetter <daniel.vetter@ffwll.ch>2013-11-01 10:50:22 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2013-11-01 18:24:53 +0100
commit8d2f24ca1f19e1e5ca6b941a3f6488f9ccae5390 (patch)
tree37aabe0afe812fb8ad704eaa8b913c9cbdc6e4f1
parent8409360381ebaaab82c7ab502665a29423fcdfc2 (diff)
downloadlinaro-lsk-8d2f24ca1f19e1e5ca6b941a3f6488f9ccae5390.tar.gz
drm/i915: scramble reset support for DP port CRC on vlv
They've moved the DC balance reset bit around. Again I don't think we need it, but better safe than sorry and maybe HDMI port CRC will prove useful for checking infoframes or hdmi audio. v2: Apply the suggestions from Damien's review. Reviewed-by: Damien Lespiau <damien.lespiau@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
-rw-r--r--drivers/gpu/drm/i915/i915_debugfs.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 88125161151..82c58eb1aa6 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -2026,6 +2026,9 @@ static int vlv_pipe_crc_ctl_reg(struct drm_device *dev,
enum intel_pipe_crc_source *source,
uint32_t *val)
{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ bool need_stable_symbols = false;
+
if (*source == INTEL_PIPE_CRC_SOURCE_AUTO) {
int ret = i9xx_pipe_crc_auto_source(dev, pipe, source);
if (ret)
@@ -2038,9 +2041,11 @@ static int vlv_pipe_crc_ctl_reg(struct drm_device *dev,
break;
case INTEL_PIPE_CRC_SOURCE_DP_B:
*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_B_VLV;
+ need_stable_symbols = true;
break;
case INTEL_PIPE_CRC_SOURCE_DP_C:
*val = PIPE_CRC_ENABLE | PIPE_CRC_SOURCE_DP_C_VLV;
+ need_stable_symbols = true;
break;
case INTEL_PIPE_CRC_SOURCE_NONE:
*val = 0;
@@ -2049,6 +2054,29 @@ static int vlv_pipe_crc_ctl_reg(struct drm_device *dev,
return -EINVAL;
}
+ /*
+ * When the pipe CRC tap point is after the transcoders we need
+ * to tweak symbol-level features to produce a deterministic series of
+ * symbols for a given frame. We need to reset those features only once
+ * a frame (instead of every nth symbol):
+ * - DC-balance: used to ensure a better clock recovery from the data
+ * link (SDVO)
+ * - DisplayPort scrambling: used for EMI reduction
+ */
+ if (need_stable_symbols) {
+ uint32_t tmp = I915_READ(PORT_DFT2_G4X);
+
+ WARN_ON(!IS_G4X(dev));
+
+ tmp |= DC_BALANCE_RESET_VLV;
+ if (pipe == PIPE_A)
+ tmp |= PIPE_A_SCRAMBLE_RESET;
+ else
+ tmp |= PIPE_B_SCRAMBLE_RESET;
+
+ I915_WRITE(PORT_DFT2_G4X, tmp);
+ }
+
return 0;
}
@@ -2128,6 +2156,22 @@ static int i9xx_pipe_crc_ctl_reg(struct drm_device *dev,
return 0;
}
+static void vlv_undo_pipe_scramble_reset(struct drm_device *dev,
+ enum pipe pipe)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ uint32_t tmp = I915_READ(PORT_DFT2_G4X);
+
+ if (pipe == PIPE_A)
+ tmp &= ~PIPE_A_SCRAMBLE_RESET;
+ else
+ tmp &= ~PIPE_B_SCRAMBLE_RESET;
+ if (!(tmp & PIPE_SCRAMBLE_RESET_MASK))
+ tmp &= ~DC_BALANCE_RESET_VLV;
+ I915_WRITE(PORT_DFT2_G4X, tmp);
+
+}
+
static void g4x_undo_pipe_scramble_reset(struct drm_device *dev,
enum pipe pipe)
{
@@ -2267,6 +2311,8 @@ static int pipe_crc_set_source(struct drm_device *dev, enum pipe pipe,
if (IS_G4X(dev))
g4x_undo_pipe_scramble_reset(dev, pipe);
+ else if (IS_VALLEYVIEW(dev))
+ vlv_undo_pipe_scramble_reset(dev, pipe);
}
return 0;