On 6/25/26 11:04, Nick Haghiri wrote:
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Commit c97da4785b3b ("drm/amd/display: Add an HPD filter for HDMI") and
commit 6a681cd90345 ("drm/amd/display: Add an hdmi_hpd_debounce_delay_ms
module") added a filter that, on an HDMI disconnect, waits
hdmi_hpd_debounce_delay_ms and suppresses the hotplug if the sink comes
back with an unchanged EDID, instead of churning userspace.
DisplayPort SST sinks show the same pattern: some monitors briefly drop
and re-assert HPD when they enter deep sleep after DPMS-off. On the DP
path that toggle is forwarded as a real hotplug, so the compositor
re-probes and re-enables the output and the panel can never stay powered
off while connected.
Extend the existing filter to DisplayPort SST behind a new
dp_hpd_debounce_delay_ms module parameter (default 0/off, mirroring the
HDMI knob). eDP and MST are excluded; are_sinks_equal() and the debounce
work are reused unchanged.
Signed-off-by: Nick Haghiri <[email protected]>
---
RFC notes / open questions (below the --- so they stay out of the commit):
- Near-mechanical port of the HDMI filter to DisplayPort SST. I run it
daily on an RX 9070 XT (RDNA4) driving an MSI MPG 274U over DP, which
briefly drops and re-asserts HPD on DPMS-off and otherwise keeps the
panel from staying asleep; dp_hpd_debounce_delay_ms=1500 fixes it.
- The DP path reuses the existing debounce work and ->hdmi_prev_sink, so
those names are now a little misleading. Happy to rename them to a
generic hpd_* if you'd prefer.
- I added a separate dp_hpd_debounce_delay_ms knob to mirror the HDMI
one; folding both into a single hpd_debounce_delay_ms applied by signal
type would work too. Let me know which you'd rather have.
Hey Nick, thank you for this patch.
I don't think I've encountered a situation when a monitor with DP can
wake a system up from DPMS, so that's interesting. What distro and
desktop environment are you using? I'd like to reproduce this issue and
help with it.
I think generalizing the hpd_debounce_delay for both DP and HDMI would
be better. Maybe we can also enable hpd_debounce_delay by default
for monitors, that are known to have this issue, using apply_edid_quirks
drivers/gpu/drm/amd/amdgpu/amdgpu.h | 1 +
drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 12 +++++++++
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h | 6 +++++
.../display/amdgpu_dm/amdgpu_dm_connector.c | 20 ++++++++-------
.../drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c | 25 ++++++++++++-------
5 files changed, 46 insertions(+), 18 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index e2d4be3c1..c085a6cc1 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -271,6 +271,7 @@ extern int amdgpu_user_queue;
extern int amdgpu_ptl;
extern uint amdgpu_hdmi_hpd_debounce_delay_ms;
+extern uint amdgpu_dp_hpd_debounce_delay_ms;
#define AMDGPU_SG_THRESHOLD (256*1024*1024)
#define AMDGPU_WAIT_IDLE_TIMEOUT_IN_MS 3000
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 65f2de86f..78df53b8c 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -246,6 +246,7 @@ int amdgpu_umsch_mm_fwlog;
int amdgpu_rebar = -1; /* auto */
int amdgpu_user_queue = -1;
uint amdgpu_hdmi_hpd_debounce_delay_ms;
+uint amdgpu_dp_hpd_debounce_delay_ms;
int amdgpu_ptl = -1; /* auto */
DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
@@ -1113,6 +1114,17 @@ module_param_named(user_queue, amdgpu_user_queue, int,
0444);
MODULE_PARM_DESC(hdmi_hpd_debounce_delay_ms, "HDMI HPD disconnect debounce delay
in milliseconds (0 to disable (by default), 1500 is common)");
module_param_named(hdmi_hpd_debounce_delay_ms,
amdgpu_hdmi_hpd_debounce_delay_ms, uint, 0644);
+/*
+ * DOC: dp_hpd_debounce_delay_ms (uint)
+ * DisplayPort SST HPD disconnect debounce delay in milliseconds.
+ *
+ * Used to filter short disconnect->reconnect HPD toggles some DisplayPort SST
+ * sinks generate while entering/leaving power save. Set to 0 to disable by
+ * default. eDP and MST are not affected.
+ */
+MODULE_PARM_DESC(dp_hpd_debounce_delay_ms, "DisplayPort SST HPD disconnect debounce
delay in milliseconds (0 to disable (by default), 1500 is common)");
+module_param_named(dp_hpd_debounce_delay_ms, amdgpu_dp_hpd_debounce_delay_ms,
uint, 0644);
+
/**
* DOC: ptl (int)
* Enable PTL feature at boot time. Possible values:
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
index 2f4a56741..abc17f547 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -64,6 +64,11 @@ enum amd_vsdb_panel_type {
* Maximum HDMI HPD debounce delay in milliseconds
*/
#define AMDGPU_DM_MAX_HDMI_HPD_DEBOUNCE_MS 5000
+
+/*
+ * Maximum DisplayPort SST HPD debounce delay in milliseconds
+ */
+#define AMDGPU_DM_MAX_DP_HPD_DEBOUNCE_MS 5000
/*
#include "include/amdgpu_dal_power_if.h"
#include "amdgpu_dm_irq.h"
@@ -875,6 +880,7 @@ struct amdgpu_dm_connector {
/* HDMI HPD debounce support */
unsigned int hdmi_hpd_debounce_delay_ms;
+ unsigned int dp_hpd_debounce_delay_ms;
struct delayed_work hdmi_hpd_debounce_work;
struct dc_sink *hdmi_prev_sink;
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
index 6143cdcf2..c79a8ada8 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
@@ -1747,8 +1747,8 @@ static void amdgpu_dm_connector_destroy(struct
drm_connector *connector)
if (aconnector->mst_mgr.dev)
drm_dp_mst_topology_mgr_destroy(&aconnector->mst_mgr);
- /* Cancel and flush any pending HDMI HPD debounce work */
- if (aconnector->hdmi_hpd_debounce_delay_ms) {
+ /* Cancel and flush any pending HPD debounce work */
+ if (aconnector->hdmi_hpd_debounce_delay_ms ||
aconnector->dp_hpd_debounce_delay_ms) {
cancel_delayed_work_sync(&aconnector->hdmi_hpd_debounce_work);
if (aconnector->hdmi_prev_sink) {
dc_sink_release(aconnector->hdmi_prev_sink);
@@ -2829,16 +2829,18 @@ void amdgpu_dm_connector_init_helper(struct
amdgpu_display_manager *dm,
mutex_init(&aconnector->handle_mst_msg_ready);
/*
- * If HDMI HPD debounce delay is set, use the minimum between selected
- * value and AMDGPU_DM_MAX_HDMI_HPD_DEBOUNCE_MS
+ * If an HPD debounce delay is set, clamp each signal's delay to its
+ * maximum. The debounce work and cached sink are shared by both the
+ * HDMI and DisplayPort SST paths.
*/
- if (amdgpu_hdmi_hpd_debounce_delay_ms) {
- aconnector->hdmi_hpd_debounce_delay_ms =
min(amdgpu_hdmi_hpd_debounce_delay_ms,
-
AMDGPU_DM_MAX_HDMI_HPD_DEBOUNCE_MS);
+ aconnector->hdmi_hpd_debounce_delay_ms =
amdgpu_hdmi_hpd_debounce_delay_ms ?
+ min(amdgpu_hdmi_hpd_debounce_delay_ms,
AMDGPU_DM_MAX_HDMI_HPD_DEBOUNCE_MS) : 0;
+ aconnector->dp_hpd_debounce_delay_ms = amdgpu_dp_hpd_debounce_delay_ms ?
+ min(amdgpu_dp_hpd_debounce_delay_ms,
AMDGPU_DM_MAX_DP_HPD_DEBOUNCE_MS) : 0;
+
+ if (aconnector->hdmi_hpd_debounce_delay_ms ||
aconnector->dp_hpd_debounce_delay_ms) {
INIT_DELAYED_WORK(&aconnector->hdmi_hpd_debounce_work,
amdgpu_dm_hdmi_hpd_debounce_work);
aconnector->hdmi_prev_sink = NULL;
- } else {
- aconnector->hdmi_hpd_debounce_delay_ms = 0;
}
dm->hdmi_frl_status_polling_delay_ms = 200;
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c
index 85711a2f2..2a732d19b 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c
@@ -1302,6 +1302,7 @@ static void handle_hpd_irq_helper(struct
amdgpu_dm_connector *aconnector,
struct dc *dc = aconnector->dc_link->ctx->dc;
bool ret = false;
bool debounce_required = false;
+ unsigned int debounce_delay_ms = 0;
if (adev->dm.disable_hpd_irq)
return;
@@ -1325,10 +1326,16 @@ static void handle_hpd_irq_helper(struct
amdgpu_dm_connector *aconnector,
drm_err(adev_to_drm(adev), "KMS: Failed to detect
connector\n");
/*
- * Check for HDMI disconnect with debounce enabled.
+ * Check for an HDMI or DisplayPort SST disconnect with debounce
+ * enabled. eDP and MST are intentionally excluded.
*/
- debounce_required = (aconnector->hdmi_hpd_debounce_delay_ms > 0 &&
- dc_is_hdmi_signal(aconnector->dc_link->connector_signal)
&&
+ if (dc_is_hdmi_signal(aconnector->dc_link->connector_signal))
+ debounce_delay_ms = aconnector->hdmi_hpd_debounce_delay_ms;
+ else if (aconnector->dc_link->connector_signal == SIGNAL_TYPE_DISPLAY_PORT
&&
+ aconnector->dc_link->type != dc_connection_mst_branch)
+ debounce_delay_ms = aconnector->dp_hpd_debounce_delay_ms;
+
+ debounce_required = (debounce_delay_ms > 0 &&
new_connection_type == dc_connection_none &&
aconnector->dc_link->local_sink != NULL);
@@ -1344,12 +1351,12 @@ static void handle_hpd_irq_helper(struct
amdgpu_dm_connector *aconnector,
drm_kms_helper_connector_hotplug_event(connector);
} else if (debounce_required) {
/*
- * HDMI disconnect detected - schedule delayed work instead of
+ * Disconnect detected - schedule delayed work instead of
* processing immediately. This allows us to coalesce spurious
- * HDMI signals from physical unplugs.
+ * HDMI/DP HPD signals from physical unplugs.
*/
- drm_dbg_kms(dev, "HDMI HPD: Disconnect detected, scheduling debounce
work (%u ms)\n",
- aconnector->hdmi_hpd_debounce_delay_ms);
+ drm_dbg_kms(dev, "HPD: Disconnect detected, scheduling debounce work
(%u ms)\n",
+ debounce_delay_ms);
/* Cache the current sink for later comparison */
if (aconnector->hdmi_prev_sink)
@@ -1361,8 +1368,8 @@ static void handle_hpd_irq_helper(struct
amdgpu_dm_connector *aconnector,
/* Schedule delayed detection. */
if (mod_delayed_work(system_percpu_wq,
&aconnector->hdmi_hpd_debounce_work,
-
msecs_to_jiffies(aconnector->hdmi_hpd_debounce_delay_ms)))
- drm_dbg_kms(dev, "HDMI HPD: Re-scheduled debounce
work\n");
+ msecs_to_jiffies(debounce_delay_ms)))
+ drm_dbg_kms(dev, "HPD: Re-scheduled debounce work\n");
} else {
--
2.54.0
--
Thanks,
Ivan Lipski
