drm/amd/display: Add an hdmi_hpd_debounce_delay_ms module

[Why&How]
Right now, the HDMI HPD filter is enabled by default at 1500ms.

We want to disable it by default, as most modern displays with HDMI do
not require it for DPMS mode.

The HPD can instead be enabled as a driver parameter with a custom delay
value in ms (up to 5000ms).

Fixes: c918e75e1ed9 ("drm/amd/display: Add an HPD filter for HDMI")
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4859
Signed-off-by: Ivan Lipski <ivan.lipski@amd.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 11a36c132905c2063783fc120e6bc37143a702ce..9c11535c44c69d3ddf2571e407bb1237e8da1697 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -269,6 +269,8 @@ extern int amdgpu_rebar;
 extern int amdgpu_wbrf;
 extern int amdgpu_user_queue;
 
+extern uint amdgpu_hdmi_hpd_debounce_delay_ms;
+
 #define AMDGPU_VM_MAX_NUM_CTX                  4096
 #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 bb8d9256fae0eee4e959423c924a543c4794ecd7..d6d0a6e34c6bfc6e0d055a6261601b4567a697a6 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -247,6 +247,7 @@ 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;
 
 DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
                        "DRM_UT_CORE",
@@ -1123,6 +1124,16 @@ module_param_named(rebar, amdgpu_rebar, int, 0444);
 MODULE_PARM_DESC(user_queue, "Enable user queues (-1 = auto (default), 0 = disable, 1 = enable, 2 = enable UQs and disable KQs)");
 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);
+
 /* These devices are not supported by amdgpu.
  * They are supported by the mach64, r128, radeon drivers
  */

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 157efedda358c0ebd2e90f2556d115fb00e4643b..cb13a2b0de62ab88ab8638d7c9a563496609f5c7 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -8961,9 +8961,18 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
        mutex_init(&aconnector->hpd_lock);
        mutex_init(&aconnector->handle_mst_msg_ready);
 
-       aconnector->hdmi_hpd_debounce_delay_ms = AMDGPU_DM_HDMI_HPD_DEBOUNCE_MS;
-       INIT_DELAYED_WORK(&aconnector->hdmi_hpd_debounce_work, hdmi_hpd_debounce_work);
-       aconnector->hdmi_prev_sink = NULL;
+       /*
+        * If HDMI HPD debounce delay is set, use the minimum between selected
+        * value and AMDGPU_DM_MAX_HDMI_HPD_DEBOUNCE_MS
+        */
+       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);
+               INIT_DELAYED_WORK(&aconnector->hdmi_hpd_debounce_work, hdmi_hpd_debounce_work);
+               aconnector->hdmi_prev_sink = NULL;
+       } else {
+               aconnector->hdmi_hpd_debounce_delay_ms = 0;
+       }
 
        /*
         * configure support HPD hot plug connector_>polled default value is 0

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 f0f371718d0333bb5333c430074ebb2012c958e4..115efd8ec68b6c39f0bef25dc0c76c7c84b45b80 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
@@ -59,7 +59,10 @@
 
 #define AMDGPU_HDR_MULT_DEFAULT (0x100000000LL)
 
-#define AMDGPU_DM_HDMI_HPD_DEBOUNCE_MS 1500
+/*
+ * Maximum HDMI HPD debounce delay in milliseconds
+ */
+#define AMDGPU_DM_MAX_HDMI_HPD_DEBOUNCE_MS 5000
 /*
 #include "include/amdgpu_dal_power_if.h"
 #include "amdgpu_dm_irq.h"