When CDCLK is as low as 79200, picture gets
unstable, while DSI and DE pll values were
confirmed to be correct.
Limiting to 158400 as agreed with Ville.
Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_cdclk.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c
index ae40a8679314..2b23f8500362 100644
--- a/drivers/gpu/drm/i915/intel_cdclk.c
+++ b/drivers/gpu/drm/i915/intel_cdclk.c
@@ -2277,6 +2277,15 @@ int intel_crtc_compute_min_cdclk(const struct intel_crtc_state *crtc_state)
IS_VALLEYVIEW(dev_priv))
min_cdclk = max(320000, min_cdclk);
+ /*
+ * On Geminilake once the CDCLK gets as low as 79200
+ * picture gets unstable, despite that values are
+ * correct for DSI PLL and DE PLL.
+ */
+ if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DSI) &&
+ IS_GEMINILAKE(dev_priv))
+ min_cdclk = max(158400, min_cdclk);
+
if (min_cdclk > dev_priv->max_cdclk_freq) {
DRM_DEBUG_KMS("required cdclk (%d kHz) exceeds max (%d kHz)\n",
min_cdclk, dev_priv->max_cdclk_freq);
--
2.17.1
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