drm/amd/display: Add an hdmi_hpd_debounce_delay_ms module

commit 6a681cd9034587fe3550868bacfbd639d1c6891f upstream.

[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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index 6f5b4a0e0a343f67c309c5e24e5b9928399792ac..803b6fc360a07bb40469f733951c37b9e6695498 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -274,6 +274,8 @@ 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 3aa33c1de29b55f38969369d3dbab7cd777322ac..335f7e2f4ce557172108646fbacc1524e40ff99a 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -246,6 +246,7 @@ 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",
@@ -1128,6 +1129,16 @@ 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 eb41766449980e048c7232254530a4b5f9a60ba3..a0077fe79ed269acc6ed6cd152ece9e737b721d8 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -8717,9 +8717,18 @@ 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 8ca738957598937d243ad9e167048f129fb0aee1..adcd7ea696719aab448183353ce6d9da35d28a5e 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"