From 1f1be49fb67a58460c2216a77d3c5a8a3faa3a98 Mon Sep 17 00:00:00 2001
From: Imre Deak <imre.deak@intel.com>
Date: Mon, 28 Oct 2019 20:15:17 +0200
Subject: drm/i915: Avoid HPD poll detect triggering a new detect cycle
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Git-commit: 1f1be49fb67a58460c2216a77d3c5a8a3faa3a98
Patch-mainline: v5.4-rc7
References: bsc#1152489
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 <val.kulkov@gmail.com>
Reported-and-tested-by: wangqr <wqr.prg@gmail.com>
Cc: Val Kulkov <val.kulkov@gmail.com>
Cc: wangqr <wqr.prg@gmail.com>
Cc: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Ville Syrj채l채 <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191028181517.22602-1-imre.deak@intel.com
(cherry picked from commit a8ddac7c9f06a12227a4f5febd1cbe0575a33179)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
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 e6e8d4a82044..0a08354a6183 100644
--- a/drivers/gpu/drm/i915/display/intel_crt.c
+++ b/drivers/gpu/drm/i915/display/intel_crt.c
@@ -864,6 +864,13 @@ 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 57e9f0ba331b..2822a9f19844 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5436,6 +5436,12 @@ 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 e02f0faecf02..b030f7ae3302 100644
--- a/drivers/gpu/drm/i915/display/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/display/intel_hdmi.c
@@ -2565,6 +2565,12 @@ 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;
}
--
2.28.0