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| author | Jesse Barnes <jbarnes@virtuousgeek.org> | 2011-07-07 11:10:57 -0700 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2011-07-07 13:38:27 -0700 |
| commit | 61da5fab5a9b129cf05b1fe4666c3e45b3103fd4 (patch) | |
| tree | d32b39d60881878ae7df4818a9387a884b7fba78 | |
| parent | fe0d42203cb5616eeff68b14576a0f7e2dd56625 (diff) | |
| download | linux-3.10-61da5fab5a9b129cf05b1fe4666c3e45b3103fd4.tar.gz linux-3.10-61da5fab5a9b129cf05b1fe4666c3e45b3103fd4.tar.bz2 linux-3.10-61da5fab5a9b129cf05b1fe4666c3e45b3103fd4.zip | |
drm/i915/dp: retry link status read 3 times on failure
Especially after a hotplug or power status change, the sink may not
reply immediately to a link status query. So retry 3 times per the spec
to really make sure nothing is there.
See section 9.1 of the 1.1a DisplayPort spec.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
| -rw-r--r-- | drivers/gpu/drm/i915/intel_dp.c | 20 |
1 files changed, 13 insertions, 7 deletions
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 391b55f1cc7..86912bd737a 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -1019,14 +1019,20 @@ intel_dp_dpms(struct drm_encoder *encoder, int mode) static bool intel_dp_get_link_status(struct intel_dp *intel_dp) { - int ret; + int ret, i; + + /* Must try AUX reads for this at least 3 times */ + for (i = 0; i < 3; i++) { + ret = intel_dp_aux_native_read(intel_dp, + DP_LANE0_1_STATUS, + intel_dp->link_status, + DP_LINK_STATUS_SIZE); + if (ret == DP_LINK_STATUS_SIZE) + return true; + msleep(1); + } - ret = intel_dp_aux_native_read(intel_dp, - DP_LANE0_1_STATUS, - intel_dp->link_status, DP_LINK_STATUS_SIZE); - if (ret != DP_LINK_STATUS_SIZE) - return false; - return true; + return false; } static uint8_t |