On Thu, Jul 9, 2026 at 3:34 AM Nick Haghiri <[email protected]> wrote:
>
> Per review feedback on the DP SST debounce extension, fold
> hdmi_hpd_debounce_delay_ms and dp_hpd_debounce_delay_ms into a single
> hpd_debounce_delay_ms module parameter (eDP and MST still excluded),
> and rename the shared connector fields, work, and cached sink from
> hdmi_* to generic hpd_*.
>
> Also add an apply_edid_quirks() case for the MSI MPG 274U
> (drm_edid_encode_panel_id('M', 'S', 'I', 0x3CF0)) that enables a
> 1500ms default debounce delay for that panel, overridable by the
> module parameter.
>
> Signed-off-by: Nick Haghiri <[email protected]>
> ---
> Ivan, generalized to a single hpd_debounce_delay_ms for both HDMI and
> DP SST as suggested, and added the apply_edid_quirks() case for the
> MSI MPG 274U (1500ms default, module param still overrides it).
Can you extend this to DVI as well?
Alex
>
> Went with replacing hdmi_hpd_debounce_delay_ms rather than keeping a
> back-compat alias, since it's only a couple cycles old. Shout if you'd
> rather I keep the alias.
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu.h | 3 +-
> drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 26 +++-------
> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h | 18 +++----
> .../amd/display/amdgpu_dm/amdgpu_dm_connector.c | 29 ++++-------
> .../drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 8 +++
> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c | 58
> +++++++++++-----------
> .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.h | 2 +-
> 7 files changed, 60 insertions(+), 84 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index c085a6cc1..af1748984 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -270,8 +270,7 @@ extern int amdgpu_wbrf;
> 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;
> +extern uint amdgpu_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 78df53b8c..5ed415aa9 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -245,8 +245,7 @@ int amdgpu_damage_clips = -1; /* auto */
> 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;
> +uint amdgpu_hpd_debounce_delay_ms;
> int amdgpu_ptl = -1; /* auto */
>
> DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
> @@ -1105,25 +1104,12 @@ MODULE_PARM_DESC(user_queue, "Enable user queues (-1
> = auto (default), 0 = disab
> module_param_named(user_queue, amdgpu_user_queue, int, 0444);
>
> /*
> - * DOC: hdmi_hpd_debounce_delay_ms (uint)
> - * HDMI HPD disconnect debounce delay in milliseconds.
> - *
> - * Used to filter short disconnect->reconnect HPD toggles some HDMI sinks
> - * generate while entering/leaving power save. Set to 0 to disable by
> default.
> - */
> -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.
> + * DOC: hpd_debounce_delay_ms (uint)
> + * HDMI/DP SST HPD disconnect debounce delay in milliseconds. eDP and MST
> + * are not affected. Overrides any per-panel default set via EDID quirks.
> */
> -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);
> +MODULE_PARM_DESC(hpd_debounce_delay_ms, "HDMI/DP SST HPD disconnect debounce
> delay in milliseconds (0 to disable (by default) or use the EDID quirk
> default, 1500 is common)");
> +module_param_named(hpd_debounce_delay_ms, amdgpu_hpd_debounce_delay_ms,
> uint, 0644);
>
> /**
> * DOC: ptl (int)
> 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 abc17f547..530e63321 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> @@ -61,14 +61,9 @@ enum amd_vsdb_panel_type {
> #define AMDGPU_HDR_MULT_DEFAULT (0x100000000LL)
>
> /*
> - * Maximum HDMI HPD debounce delay in milliseconds
> + * Maximum HDMI/DP SST 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
> +#define AMDGPU_DM_MAX_HPD_DEBOUNCE_MS 5000
> /*
> #include "include/amdgpu_dal_power_if.h"
> #include "amdgpu_dm_irq.h"
> @@ -878,11 +873,10 @@ struct amdgpu_dm_connector {
> enum adaptive_sync_type as_type;
> struct amdgpu_hdmi_vsdb_info vsdb_info;
>
> - /* 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;
> + /* HDMI/DP SST HPD debounce support */
> + unsigned int hpd_debounce_delay_ms;
> + struct delayed_work hpd_debounce_work;
> + struct dc_sink *hpd_prev_sink;
>
> /* HDMI compliance automation */
> bool hdmi_comp_auto;
> 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 c79a8ada8..798825ec1 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
> @@ -1748,12 +1748,10 @@ static void amdgpu_dm_connector_destroy(struct
> drm_connector *connector)
> drm_dp_mst_topology_mgr_destroy(&aconnector->mst_mgr);
>
> /* 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);
> - aconnector->hdmi_prev_sink = NULL;
> - }
> + cancel_delayed_work_sync(&aconnector->hpd_debounce_work);
> + if (aconnector->hpd_prev_sink) {
> + dc_sink_release(aconnector->hpd_prev_sink);
> + aconnector->hpd_prev_sink = NULL;
> }
>
> if (aconnector->bl_idx != -1) {
> @@ -2828,20 +2826,11 @@ void amdgpu_dm_connector_init_helper(struct
> amdgpu_display_manager *dm,
> mutex_init(&aconnector->hpd_lock);
> mutex_init(&aconnector->handle_mst_msg_ready);
>
> - /*
> - * 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.
> - */
> - 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;
> - }
> + /* May be overridden later by an EDID quirk in apply_edid_quirks() */
> + aconnector->hpd_debounce_delay_ms = amdgpu_hpd_debounce_delay_ms ?
> + min(amdgpu_hpd_debounce_delay_ms,
> AMDGPU_DM_MAX_HPD_DEBOUNCE_MS) : 0;
> + aconnector->hpd_prev_sink = NULL;
> + INIT_DELAYED_WORK(&aconnector->hpd_debounce_work,
> amdgpu_dm_hpd_debounce_work);
>
> dm->hdmi_frl_status_polling_delay_ms = 200;
> INIT_DELAYED_WORK(&dm->hdmi_frl_status_polling_work,
> hdmi_frl_status_polling_work);
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> index 9c4e0a4e2..71c897416 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> @@ -137,6 +137,14 @@ static void apply_edid_quirks(struct dc_link *link,
> struct edid *edid,
> drm_dbg_driver(dev, "Skip PHY SSC reduction on panel id
> %X\n", panel_id);
> link->wa_flags.skip_phy_ssc_reduction = true;
> break;
> + /* Workaround for monitors that toggle HPD on entering deep sleep */
> + case drm_edid_encode_panel_id('M', 'S', 'I', 0x3CF0):
> + if (!aconnector->hpd_debounce_delay_ms) {
> + drm_dbg_driver(dev, "Enabling HPD debounce on panel
> id %X\n", panel_id);
> + aconnector->hpd_debounce_delay_ms =
> + min(1500U, AMDGPU_DM_MAX_HPD_DEBOUNCE_MS);
> + }
> + break;
> default:
> return;
> }
> 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 2a732d19b..e423dbe9b 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
> @@ -1217,13 +1217,13 @@ EXPORT_IF_KUNIT(are_sinks_equal);
>
>
> /**
> - * DOC: amdgpu_dm_hdmi_hpd_debounce_work
> + * DOC: amdgpu_dm_hpd_debounce_work
> *
> - * HDMI HPD debounce delay in milliseconds. When an HDMI display toggles HPD
> + * HDMI/DP SST HPD debounce delay in milliseconds. When a display toggles HPD
> * (such as during power save transitions), this delay determines how long to
> * wait before processing the HPD event. This allows distinguishing between a
> - * physical unplug (>hdmi_hpd_debounce_delay)
> - * and a spontaneous RX HPD toggle (<hdmi_hpd_debounce_delay).
> + * physical unplug (>hpd_debounce_delay)
> + * and a spontaneous RX HPD toggle (<hpd_debounce_delay).
> *
> * If the toggle is less than this delay, the driver compares sink
> capabilities
> * and permits a hotplug event if they changed.
> @@ -1231,11 +1231,11 @@ EXPORT_IF_KUNIT(are_sinks_equal);
> * The default value of 1500ms was chosen based on experimental testing with
> * various monitors that exhibit spontaneous HPD toggling behavior.
> */
> -void amdgpu_dm_hdmi_hpd_debounce_work(struct work_struct *work)
> +void amdgpu_dm_hpd_debounce_work(struct work_struct *work)
> {
> struct amdgpu_dm_connector *aconnector =
> container_of(to_delayed_work(work), struct
> amdgpu_dm_connector,
> - hdmi_hpd_debounce_work);
> + hpd_debounce_work);
> struct drm_connector *connector = &aconnector->base;
> struct drm_device *dev = connector->dev;
> struct amdgpu_device *adev = drm_to_adev(dev);
> @@ -1259,11 +1259,12 @@ void amdgpu_dm_hdmi_hpd_debounce_work(struct
> work_struct *work)
> /* Apply workaround delay for certain panels */
> amdgpu_dm_apply_delay_after_dpcd_poweroff(adev,
> aconnector->dc_sink);
> /* Compare sinks to determine if this was a spontaneous HPD
> toggle */
> - if (are_sinks_equal(aconnector->dc_link->local_sink,
> aconnector->hdmi_prev_sink)) {
> + if (are_sinks_equal(aconnector->dc_link->local_sink,
> aconnector->hpd_prev_sink)) {
> /*
> - * Sinks match - this was a spontaneous HDMI HPD
> toggle.
> + * Sinks match - this was a spontaneous HPD toggle.
> */
> - drm_dbg_kms(dev, "HDMI HPD: Sink unchanged after
> debounce, internal re-enable\n");
> + drm_dbg_kms(dev,
> + "HPD: Sink unchanged after debounce,
> internal re-enable\n");
> fake_reconnect = true;
> }
>
> @@ -1280,9 +1281,9 @@ void amdgpu_dm_hdmi_hpd_debounce_work(struct
> work_struct *work)
> }
>
> /* Release the cached sink reference */
> - if (aconnector->hdmi_prev_sink) {
> - dc_sink_release(aconnector->hdmi_prev_sink);
> - aconnector->hdmi_prev_sink = NULL;
> + if (aconnector->hpd_prev_sink) {
> + dc_sink_release(aconnector->hpd_prev_sink);
> + aconnector->hpd_prev_sink = NULL;
> }
>
> scoped_guard(mutex, &adev->dm.dc_lock) {
> @@ -1302,7 +1303,7 @@ 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;
> + bool debounce_eligible;
>
> if (adev->dm.disable_hpd_irq)
> return;
> @@ -1329,13 +1330,12 @@ static void handle_hpd_irq_helper(struct
> amdgpu_dm_connector *aconnector,
> * Check for an HDMI or DisplayPort SST disconnect with debounce
> * enabled. eDP and MST are intentionally excluded.
> */
> - 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_eligible =
> dc_is_hdmi_signal(aconnector->dc_link->connector_signal) ||
> + (aconnector->dc_link->connector_signal ==
> SIGNAL_TYPE_DISPLAY_PORT &&
> + aconnector->dc_link->type !=
> dc_connection_mst_branch);
>
> - debounce_required = (debounce_delay_ms > 0 &&
> + debounce_required = (debounce_eligible &&
> + aconnector->hpd_debounce_delay_ms > 0 &&
> new_connection_type == dc_connection_none &&
> aconnector->dc_link->local_sink != NULL);
>
> @@ -1356,25 +1356,25 @@ static void handle_hpd_irq_helper(struct
> amdgpu_dm_connector *aconnector,
> * HDMI/DP HPD signals from physical unplugs.
> */
> drm_dbg_kms(dev, "HPD: Disconnect detected, scheduling
> debounce work (%u ms)\n",
> - debounce_delay_ms);
> + aconnector->hpd_debounce_delay_ms);
>
> /* Cache the current sink for later comparison */
> - if (aconnector->hdmi_prev_sink)
> - dc_sink_release(aconnector->hdmi_prev_sink);
> - aconnector->hdmi_prev_sink = aconnector->dc_link->local_sink;
> - if (aconnector->hdmi_prev_sink)
> - dc_sink_retain(aconnector->hdmi_prev_sink);
> + if (aconnector->hpd_prev_sink)
> + dc_sink_release(aconnector->hpd_prev_sink);
> + aconnector->hpd_prev_sink = aconnector->dc_link->local_sink;
> + if (aconnector->hpd_prev_sink)
> + dc_sink_retain(aconnector->hpd_prev_sink);
>
> /* Schedule delayed detection. */
> if (mod_delayed_work(system_percpu_wq,
> - &aconnector->hdmi_hpd_debounce_work,
> - msecs_to_jiffies(debounce_delay_ms)))
> + &aconnector->hpd_debounce_work,
> +
> msecs_to_jiffies(aconnector->hpd_debounce_delay_ms)))
> drm_dbg_kms(dev, "HPD: Re-scheduled debounce work\n");
>
> } else {
>
> - /* If the aconnector->hdmi_hpd_debounce_work is scheduled,
> exit early */
> - if (delayed_work_pending(&aconnector->hdmi_hpd_debounce_work))
> + /* If the aconnector->hpd_debounce_work is scheduled, exit
> early */
> + if (delayed_work_pending(&aconnector->hpd_debounce_work))
> return;
>
> scoped_guard(mutex, &adev->dm.dc_lock) {
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.h
> b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.h
> index bccb5d354..66fb82961 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.h
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.h
> @@ -113,7 +113,7 @@ void amdgpu_dm_irq_resume_late(struct amdgpu_device
> *adev);
> struct hpd_rx_irq_offload_work_queue
> *amdgpu_dm_hpd_rx_irq_create_workqueue(struct amdgpu_device *adev);
> void amdgpu_dm_hpd_rx_irq_work_suspend(struct amdgpu_display_manager *dm);
> int amdgpu_dm_register_hpd_handlers(struct amdgpu_device *adev);
> -void amdgpu_dm_hdmi_hpd_debounce_work(struct work_struct *work);
> +void amdgpu_dm_hpd_debounce_work(struct work_struct *work);
>
> /* IRQ handlers */
> struct amdgpu_crtc *amdgpu_dm_get_crtc_by_otg_inst(struct amdgpu_device
> *adev,
>
> ---
> base-commit: c92b5b607c1c8ab786fccf03d62352b82f6539ae
> change-id: 20260708-hpd-debounce-unify-896ad367bf02
>
> Best regards,
> --
> Nick Haghiri <[email protected]>
>
