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-rw-r--r--drivers/gpu/drm/i915/intel_dp.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index f9c5f17..464d8ad 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4498,6 +4498,18 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
if (intel_dig_port->base.type != INTEL_OUTPUT_EDP)
intel_dig_port->base.type = INTEL_OUTPUT_DISPLAYPORT;
+ if (long_hpd && intel_dig_port->base.type == INTEL_OUTPUT_EDP) {
+ /*
+ * vdd off can generate a long pulse on eDP which
+ * would require vdd on to handle it, and thus we
+ * would end up in an endless cycle of
+ * "vdd off -> long hpd -> vdd on -> detect -> vdd off -> ..."
+ */
+ DRM_DEBUG_KMS("ignoring long hpd on eDP port %c\n",
+ port_name(intel_dig_port->port));
+ return false;
+ }
+
DRM_DEBUG_KMS("got hpd irq on port %c - %s\n",
port_name(intel_dig_port->port),
long_hpd ? "long" : "short");
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