If ->detect is called too soon after a hot plug event, the sink may not be ready yet. So try up to 3 times with 1ms sleeps in between tries to get the data (spec dictates that receivers must be ready to respond within 1ms and that sources should try 3 times).
See section 9.1 of the 1.1a DisplayPort spec. Signed-off-by: Jesse Barnes <[email protected]> --- drivers/gpu/drm/i915/intel_dp.c | 15 ++++++++++----- 1 files changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index a9a5051..70075d9 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -1551,6 +1551,7 @@ static enum drm_connector_status ironlake_dp_detect(struct intel_dp *intel_dp) { enum drm_connector_status status; + int ret, i; /* Can't disconnect eDP, but you can close the lid... */ if (is_edp(intel_dp)) { @@ -1561,12 +1562,16 @@ ironlake_dp_detect(struct intel_dp *intel_dp) } status = connector_status_disconnected; - if (intel_dp_aux_native_read(intel_dp, - 0x000, intel_dp->dpcd, - sizeof (intel_dp->dpcd)) - == sizeof(intel_dp->dpcd)) { - if (intel_dp->dpcd[DP_DPCD_REV] != 0) + for (i = 0; i < 3; i++) { + ret = intel_dp_aux_native_read(intel_dp, + 0x000, intel_dp->dpcd, + sizeof (intel_dp->dpcd)); + if (ret == sizeof(intel_dp->dpcd) && + intel_dp->dpcd[DP_DPCD_REV] != 0) { status = connector_status_connected; + break; + } + msleep(1); } DRM_DEBUG_KMS("DPCD: %hx%hx%hx%hx\n", intel_dp->dpcd[0], intel_dp->dpcd[1], intel_dp->dpcd[2], intel_dp->dpcd[3]); -- 1.7.4.1 _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
