drm/i915: use 125MHz reference clock for PCH attached eDP
Fix the test so we don't try to use the 450MHz refclk on PCH attached
eDP.
References:
https://bugs.freedesktop.org/show_bug.cgi?id=29141
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 38bf7cd..8c1da1e 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -246,8 +246,11 @@
/* The clock divider is based off the hrawclk,
* and would like to run at 2MHz. So, take the
* hrawclk value and divide by 2 and use that
+ *
+ * Note that PCH attached eDP panels should use a 125MHz input
+ * clock divider.
*/
- if (IS_eDP(intel_dp)) {
+ if (IS_eDP(intel_dp) && !IS_PCH_eDP(intel_dp)) {
if (IS_GEN6(dev))
aux_clock_divider = 200; /* SNB eDP input clock at 400Mhz */
else