[Intel-gfx] [PATCH] drm/i915: increase the tries for HDMI hotplug live status checking

Gary Wang gary.c.wang at intel.com
Wed Dec 23 00:11:35 PST 2015

The total delay of HDMI hotplug detecting with 30ms is sometimes not
enoughtfor HDMI live status up with specific HDMI monitors in BSW platform.

After doing experiments for following monitors, it needs 80ms at least
for those worst cases.

Lenovo L246 1xwA (4 failed, necessary hot-plug delay: 58/40/60/40ms)
Philips HH2AP (9 failed, necessary hot-plug delay: 80/50/50/60/46/40/58/58/39ms)
BENQ ET-0035-N (6 failed, necessary hot-plug delay: 60/50/50/80/80/40ms)
DELL U2713HM (2 failed, necessary hot-plug delay: 58/59ms)
HP HP-LP2475w (5 failed, necessary hot-plug delay: 70/50/40/60/40ms)

It looks like 70-80 ms is BSW platform needs in some bad cases of the
monitors at this end (8 times delay at most). Keep less than 100ms for
HDCP pulse HPD low (with at least 100ms) to respond a plug out.

Reviewed-by: Cooper Chiou <cooper.chiou at intel.com>
Tested-by: Gary Wang <gary.c.wang at intel.com>
Cc: Gavin Hindman <gavin.hindman at intel.com>
Cc: Sonika Jindal <sonika.jindal at intel.com>
Cc: Shashank Sharma <shashank.sharma at intel.com>
Cc: Shobhit Kumar <shobhit.kumar at intel.com>
Signed-off-by: Gary Wang <gary.c.wang at intel.com>
 drivers/gpu/drm/i915/intel_hdmi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 mode change 100644 => 100755 drivers/gpu/drm/i915/intel_hdmi.c

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
old mode 100644
new mode 100755
index 6214175..4a77639
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1392,7 +1392,7 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
 	intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS);
-	for (try = 0; !live_status && try < 4; try++) {
+	for (try = 0; !live_status && try < 9; try++) {
 		if (try)
 		live_status = intel_digital_port_connected(dev_priv,

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