diff options
| author | Daniel Vetter <[email protected]> | 2012-06-14 22:15:00 +0200 |
|---|---|---|
| committer | Daniel Vetter <[email protected]> | 2012-06-16 15:39:02 +0200 |
| commit | 6b4e0a93ff6e45714c72bdce193f719ed94810e3 (patch) | |
| tree | 0feef6b03bcc465f48d7d1e315d46b5af3246a08 | |
| parent | 351cfc34db8decb0c5cc1aac7cf1780a0e45c8b1 (diff) | |
Revert "drm/i915/dp: Use auxch precharge value of 5 everywhere"
This reverts commit 092945e11c5b84f66dd08f0b87fb729715d377bc.
This commit prevents a DP screen from properly training the link.
Oddly enough it works, once the machine has been warm-booted with an
older kernel.
According to DP docs this _should_ have been the right precharge time.
Also, the commit that originally introduces this was just general snb
DP enabling and didn't mention any specific reason for this special
value. Whatever, trust the reporter that this makes things worse and
let's just revert it.
v2: Less spelling fail.
Cc: Adam Jackson <[email protected]>
Cc: Jesse Barnes <[email protected]>
Reported-by: "Wouter M. Koolen" <[email protected]>
Buglink: https://lkml.org/lkml/2012/6/14/301
Cc: [email protected] (only for 3.4)
Signed-Off-by: Daniel Vetter <[email protected]>
| -rw-r--r-- | drivers/gpu/drm/i915/intel_dp.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index c574ff0189de..a4b3887575a1 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -371,7 +371,7 @@ intel_dp_aux_ch(struct intel_dp *intel_dp, int recv_bytes; uint32_t status; uint32_t aux_clock_divider; - int try, precharge = 5; + int try, precharge; intel_dp_check_edp(intel_dp); /* The clock divider is based off the hrawclk, @@ -391,6 +391,11 @@ intel_dp_aux_ch(struct intel_dp *intel_dp, else aux_clock_divider = intel_hrawclk(dev) / 2; + if (IS_GEN6(dev)) + precharge = 3; + else + precharge = 5; + /* Try to wait for any previous AUX channel activity */ for (try = 0; try < 3; try++) { status = I915_READ(ch_ctl); |