3.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: Takashi Iwai <tiwai@xxxxxxx>
commit 9d1a455b0ca1c2c956b4d9ab212864a8695270f1 upstream.
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
by the commit [71244653: drm/i915: adjusted_mode->clock in the dp
mode_fix].
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.
v1->v2: Use intel_edp_target_clock() for checking eDP fixed clock
instead of open code as in ironlake_set_m_n().
Backported for 3.8-stable. Reverted refactoring in e69d0bc1.
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Signed-off-by: Lingzhu Xiang <lxiang@xxxxxxxxxx>
Reviewed-by: CAI Qian <caiqian@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dp.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -788,6 +788,7 @@ intel_dp_set_m_n(struct drm_crtc *crtc,
struct intel_dp_m_n m_n;
int pipe = intel_crtc->pipe;
enum transcoder cpu_transcoder = intel_crtc->cpu_transcoder;
+ int target_clock;
/*
* Find the lane count in the intel_encoder private
@@ -803,13 +804,22 @@ intel_dp_set_m_n(struct drm_crtc *crtc,
}
}
+ target_clock = mode->clock;
+ for_each_encoder_on_crtc(dev, crtc, intel_encoder) {
+ if (intel_encoder->type == INTEL_OUTPUT_EDP) {
+ target_clock = intel_edp_target_clock(intel_encoder,
+ mode);
+ break;
+ }
+ }
+
/*
* Compute the GMCH and Link ratios. The '3' here is
* the number of bytes_per_pixel post-LUT, which we always
* set up for 8-bits of R/G/B, or 3 bytes total.
*/
intel_dp_compute_m_n(intel_crtc->bpp, lane_count,
- mode->clock, adjusted_mode->clock, &m_n);
+ target_clock, adjusted_mode->clock, &m_n);
if (IS_HASWELL(dev)) {
I915_WRITE(PIPE_DATA_M1(cpu_transcoder),
--
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