diff options
| author | Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com> | 2018-09-27 23:57:30 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-11-21 11:22:13 +0300 |
| commit | 6440b1a7f8f2698f7f128c9503ae103247a17151 (patch) | |
| tree | e205bd975fe2cab98e9cc8c818847c71f6a27178 | |
| parent | f28285d100212361ddc832742b760169b75dce07 (diff) | |
| download | linux-6440b1a7f8f2698f7f128c9503ae103247a17151.tar.xz | |
drm/i915/dp: Fix link retraining comment in intel_dp_long_pulse()
commit 49af5d95b9b3c21a84ad115a9db9acbc036d849a upstream.
Comment claims link needs to be retrained because the connected sink raised
a long pulse to indicate link loss. If the sink did so,
intel_dp_hotplug() would have handled link retraining. Looking at the
logs in Bugzilla referenced in commit '3cf71bc9904d ("drm/i915: Re-apply
Perform link quality check, unconditionally during long pulse"")', the
issue is that the sink does not trigger an interrupt. What we want is
->detect() from user space to check link status and retrain. Ville's
review for the original patch also indicates the same root cause. So,
rewrite the comment.
v2: Patch split and rewrote comment.
Cc: Lyude Paul <lyude@redhat.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Jan-Marek Glogowski <glogow@fbihome.de>
References: 3cf71bc9904d ("drm/i915: Re-apply "Perform link quality check, unconditionally during long pulse"")
Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180927205735.16651-1-dhinakaran.pandiyan@intel.com
(cherry picked from commit 9ebd8202393dde9d3678c9ec162c1aa63ba17eac)
Fixes: 399334708b4f ("drm/i915: Re-apply "Perform link quality check, unconditionally during long pulse"")
Cc: stable@vger.kernel.org
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/gpu/drm/i915/intel_dp.c | 13 |
1 files changed, 3 insertions, 10 deletions
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 2a41048d914b..c4ab987f26df 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -4874,16 +4874,9 @@ intel_dp_long_pulse(struct intel_connector *connector, goto out; } else { /* - * If display is now connected check links status, - * there has been known issues of link loss triggering - * long pulse. - * - * Some sinks (eg. ASUS PB287Q) seem to perform some - * weird HPD ping pong during modesets. So we can apparently - * end up with HPD going low during a modeset, and then - * going back up soon after. And once that happens we must - * retrain the link to get a picture. That's in case no - * userspace component reacted to intermittent HPD dip. + * Some external monitors do not signal loss of link + * synchronization with an IRQ_HPD, so force a link status + * check. */ struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base; |