From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Mon, 28 Oct 2019 20:15:17 +0200 Subject: [PATCH] drm/i915: Avoid HPD poll detect triggering a new detect cycle MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit For the HPD interrupt functionality the HW depends on power wells in the display core domain to be on. Accordingly when enabling these power wells the HPD polling logic will force an HPD detection cycle to account for hotplug events that may have happened when such a power well was off. Thus a detect cycle started by polling could start a new detect cycle if a power well in the display core domain gets enabled during detect and stays enabled after detect completes. That in turn can lead to a detection cycle runaway. To prevent re-triggering a poll-detect cycle make sure we drop all power references we acquired during detect synchronously by the end of detect. This will let the poll-detect logic continue with polling (matching the off state of the corresponding power wells) instead of scheduling a new detection cycle. Fixes: 6cfe7ec02e85 ("drm/i915: Remove the unneeded AUX power ref from intel_dp_detect()") Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112125 Reported-and-tested-by: Val Kulkov Reported-and-tested-by: wangqr Cc: Val Kulkov Cc: wangqr Cc: Ville Syrjälä Signed-off-by: Imre Deak Reviewed-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20191028181517.22602-1-imre.deak@intel.com (cherry picked from commit a8ddac7c9f06a12227a4f5febd1cbe0575a33179) Signed-off-by: Thomas Lamprecht --- drivers/gpu/drm/i915/display/intel_crt.c | 7 +++++++ drivers/gpu/drm/i915/display/intel_dp.c | 6 ++++++ drivers/gpu/drm/i915/display/intel_hdmi.c | 6 ++++++ 3 files changed, 19 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_crt.c b/drivers/gpu/drm/i915/display/intel_crt.c index 3fcf2f84bcce..da1d6be46a0c 100644 --- a/drivers/gpu/drm/i915/display/intel_crt.c +++ b/drivers/gpu/drm/i915/display/intel_crt.c @@ -867,6 +867,13 @@ intel_crt_detect(struct drm_connector *connector, out: intel_display_power_put(dev_priv, intel_encoder->power_domain, wakeref); + + /* + * Make sure the refs for power wells enabled during detect are + * dropped to avoid a new detect cycle triggered by HPD polling. + */ + intel_display_power_flush_work(dev_priv); + return status; } diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 4b4d516b15e0..106b666a2cc3 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -5649,6 +5649,12 @@ intel_dp_detect(struct drm_connector *connector, if (status != connector_status_connected && !intel_dp->is_mst) intel_dp_unset_edid(intel_dp); + /* + * Make sure the refs for power wells enabled during detect are + * dropped to avoid a new detect cycle triggered by HPD polling. + */ + intel_display_power_flush_work(dev_priv); + return status; } diff --git a/drivers/gpu/drm/i915/display/intel_hdmi.c b/drivers/gpu/drm/i915/display/intel_hdmi.c index 7ffdfaae7188..5d5453461a6f 100644 --- a/drivers/gpu/drm/i915/display/intel_hdmi.c +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c @@ -2571,6 +2571,12 @@ intel_hdmi_detect(struct drm_connector *connector, bool force) if (status != connector_status_connected) cec_notifier_phys_addr_invalidate(intel_hdmi->cec_notifier); + /* + * Make sure the refs for power wells enabled during detect are + * dropped to avoid a new detect cycle triggered by HPD polling. + */ + intel_display_power_flush_work(dev_priv); + return status; }