From 43ba5e0a17978afdc0bd83e65155e6f759af3752 Mon Sep 17 00:00:00 2001 From: Jan-Marek Glogowski Date: Sat, 25 Aug 2018 15:10:35 -0400 Subject: [PATCH] drm/i915: Re-apply "Perform link quality check, unconditionally during long pulse" This re-applies the workaround for "some DP sinks, [which] are a little nuts" from commit 36c7558ab565 ("drm/i915: Perform link quality check unconditionally during long pulse"). It makes the secondary AOC E2460P monitor connected via DP to an acer Veriton N4640G usable again. This hunk was dropped in commit 96337bcf36f6 ("drm/i915: Move SST DP link retraining into the ->post_hotplug() hook") Fixes: 96337bcf36f6 ("drm/i915: Move SST DP link retraining into the ->post_hotplug() hook") [Cleaned up commit message, added stable cc] Signed-off-by: Lyude Paul Signed-off-by: Jan-Marek Glogowski Cc: stable@vger.kernel.org Link: https://patchwork.freedesktop.org/patch/msgid/20180825191035.3945-1-lyude@redhat.com --- drivers/gpu/drm/i915/intel_dp.c | 33 +++++++++++++++++++-------------- 1 file changed, 19 insertions(+), 14 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index b3f6f04c3c7de..db8515171270a 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -4333,18 +4333,6 @@ intel_dp_needs_link_retrain(struct intel_dp *intel_dp) return !drm_dp_channel_eq_ok(link_status, intel_dp->lane_count); } -/* - * 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. - */ int intel_dp_retrain_link(struct intel_encoder *encoder, struct drm_modeset_acquire_ctx *ctx) { @@ -5031,7 +5019,8 @@ intel_dp_unset_edid(struct intel_dp *intel_dp) } static int -intel_dp_long_pulse(struct intel_connector *connector) +intel_dp_long_pulse(struct intel_connector *connector, + struct drm_modeset_acquire_ctx *ctx) { struct drm_i915_private *dev_priv = to_i915(connector->base.dev); struct intel_dp *intel_dp = intel_attached_dp(&connector->base); @@ -5090,6 +5079,22 @@ intel_dp_long_pulse(struct intel_connector *connector) */ status = connector_status_disconnected; 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. + */ + struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base; + + intel_dp_retrain_link(encoder, ctx); } /* @@ -5151,7 +5156,7 @@ intel_dp_detect(struct drm_connector *connector, return ret; } - status = intel_dp_long_pulse(intel_dp->attached_connector); + status = intel_dp_long_pulse(intel_dp->attached_connector, ctx); } intel_dp->detect_done = false; -- 2.39.5