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drm/i915/dp: try to read receiver capabilities 3 times when detecting 

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 <jbarnes@virtuousgeek.org>
Reviewed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
This commit is contained in:
Jesse Barnes 2011-07-07 11:11:00 -07:00 committed by Keith Packard
parent 59cd09e1ae
commit 899526d9a7
1 changed files with 10 additions and 5 deletions
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15
drivers/gpu/drm/i915/intel_dp.c
View File

@ -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]);