From 499e41b16a10d8e75a8870df68ee5e7f7d0ddcc5 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=utf8 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: 34e95d9cc5df ("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: Rodrigo Vivi --- 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 e6e8d4a820446..0a08354a61836 100644 --- a/drivers/gpu/drm/i915/display/intel_crt.c +++ b/drivers/gpu/drm/i915/display/intel_crt.c @@ -864,6 +864,13 @@ load_detect: 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 57e9f0ba331b4..2822a9f198440 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -5436,6 +5436,12 @@ out: 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 e02f0faecf028..b030f7ae33029 100644 --- a/drivers/gpu/drm/i915/display/intel_hdmi.c +++ b/drivers/gpu/drm/i915/display/intel_hdmi.c @@ -2565,6 +2565,12 @@ out: 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; } -- 2.39.5