The eDP output on HP Z1 is still broken when X is started even after
fixing the infinite link-train loop. The regression was introduced in
3.6 kernel for cleaning up the mode clock handling code in intel_dp.c.
In the past, the clock of the reference mode was modified in
intel_dp_mode_fixup() in the case of eDP fixed clock, and this clock was
used for calculating in intel_dp_set_m_n(). This override was removed,
thus the wrong mode clock is used for the calculation, resulting in a
psychedelic smoking output in the end.
This patch corrects the clock to be used in the place.
Cc: <stable at vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
drivers/gpu/drm/i915/intel_dp.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 7d250aa..ddbf50f 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -819,6 +819,7 @@ intel_dp_set_m_n(struct drm_crtc *crtc, struct drm_display_mode *mode,
struct intel_link_m_n m_n;
int pipe = intel_crtc->pipe;
enum transcoder cpu_transcoder = intel_crtc->cpu_transcoder;
+ int pixel_clock = mode->clock;
/*
* Find the lane count in the intel_encoder private
@@ -826,6 +827,13 @@ intel_dp_set_m_n(struct drm_crtc *crtc, struct drm_display_mode *mode,
for_each_encoder_on_crtc(dev, crtc, intel_encoder) {
intel_dp = enc_to_intel_dp(&intel_encoder->base);
+ if (intel_encoder->type == INTEL_OUTPUT_EDP) {
+ struct drm_display_mode *fixed_mode =
+ intel_dp->attached_connector->panel.fixed_mode;
+ if (fixed_mode)
+ pixel_clock = fixed_mode->clock;
+ }
+
if (intel_encoder->type == INTEL_OUTPUT_DISPLAYPORT ||
intel_encoder->type == INTEL_OUTPUT_EDP)
{
@@ -840,7 +848,7 @@ intel_dp_set_m_n(struct drm_crtc *crtc, struct drm_display_mode *mode,
* set up for 8-bits of R/G/B, or 3 bytes total.
*/
intel_link_compute_m_n(intel_crtc->bpp, lane_count,
- mode->clock, adjusted_mode->clock, &m_n);
+ pixel_clock, adjusted_mode->clock, &m_n);
if (IS_HASWELL(dev)) {
I915_WRITE(PIPE_DATA_M1(cpu_transcoder),
--
1.8.1.4
