linux-kernel - [PATCH v2 19/19] drm/amd/display: Add HDMI VRR desktop mode

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Message-ID: <20260125183914.459228-20-tomasz.pakula.oficjalny@gmail.com>
Date: Sun, 25 Jan 2026 19:39:14 +0100
From: Tomasz Pakuła <tomasz.pakula.oficjalny@...il.com>
To: alexander.deucher@....com,
	harry.wentland@....com,
	sunpeng.li@....com
Cc: maarten.lankhorst@...ux.intel.com,
	mripard@...nel.org,
	tzimmermann@...e.de,
	airlied@...il.com,
	simona@...ll.ch,
	siqueira@...lia.com,
	dri-devel@...ts.freedesktop.org,
	amd-gfx@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org,
	tomasz.pakula.oficjalny@...il.com,
	bernhard.berger@...il.com,
	michel.daenzer@...lbox.org,
	daniel@...ishbar.org
Subject: [PATCH v2 19/19] drm/amd/display: Add HDMI VRR desktop mode

[Why]
Many TVs and other HDMI sinks suffer from blanking and possibly other
glitches when VRR is toggled. With FreeSync present on such sinks, they
behave like the signal is always variable, even in fixed refresh rate
situations.

[How]
Keep HDMI VRR toggled if it's supported and not explicitly disabled.
Additionnally, add module parameter which allows users to configure HDMI
VRR triggering to only happen when the signal is truly asking for
variable state. This is useful if end user has a TV that automatically
toggles ALLM/Game mode when VRR is active and such user doesn't want
gaming mode in normal desktop usage.

Signed-off-by: Tomasz Pakuła <tomasz.pakula.oficjalny@...il.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu.h                 |  1 +
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c             | 13 +++++++++++++
 .../amd/display/modules/info_packet/info_packet.c   | 10 ++++++++--
 3 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
index c9eab44ad5b3..dddd8ed361a0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
@@ -269,6 +269,7 @@ extern int amdgpu_rebar;
 extern int amdgpu_wbrf;
 extern int amdgpu_user_queue;
 extern int amdgpu_allm_mode;
+extern bool amdgpu_hdmi_vrr_desktop_mode;
 
 extern uint amdgpu_hdmi_hpd_debounce_delay_ms;
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 3bdbb46e4d69..f4551450bf31 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -249,6 +249,7 @@ int amdgpu_rebar = -1; /* auto */
 int amdgpu_user_queue = -1;
 uint amdgpu_hdmi_hpd_debounce_delay_ms;
 int amdgpu_allm_mode = 1;
+bool amdgpu_hdmi_vrr_desktop_mode = true;
 
 DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
 			"DRM_UT_CORE",
@@ -1146,6 +1147,18 @@ module_param_named(hdmi_hpd_debounce_delay_ms, amdgpu_hdmi_hpd_debounce_delay_ms
 MODULE_PARM_DESC(allm_mode, "Changes ALLM trigger mode (0 = disable, 1 = enable (default), 2 = force enable)");
 module_param_named(allm_mode, amdgpu_allm_mode, int, 0644);
 
+/**
+ * DOC: hdmi_vrr_on_dekstop (bool)
+ * Enables FreeSync behavior mimicking by keeping HDMI VRR signalling active in
+ * fixed refresh rate conditions like normal desktop work/web browsing.
+ * Possible values:
+ *
+ * -  false = HDMI VRR is only enabled if refresh rate is truly variable
+ * -  true  = Mimics FreeSync behavior and keeps HDMI VRR always active
+ */
+MODULE_PARM_DESC(hdmi_vrr_desktop_mode, "Changes HDMI VRR desktop mode (false = disable, true = enable (default))");
+module_param_named(hdmi_vrr_desktop_mode, amdgpu_hdmi_vrr_desktop_mode, bool, 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/modules/info_packet/info_packet.c b/drivers/gpu/drm/amd/display/modules/info_packet/info_packet.c
index 38056b2d37b2..c61bbf912a8b 100644
--- a/drivers/gpu/drm/amd/display/modules/info_packet/info_packet.c
+++ b/drivers/gpu/drm/amd/display/modules/info_packet/info_packet.c
@@ -651,8 +651,14 @@ static void build_vtem_infopacket_data(const struct dc_stream_state *stream,
 	bool rb = false;
 
 	hdmi_vic_mode = is_hdmi_vic_mode(stream);
-	vrr_active = vrr->state == VRR_STATE_ACTIVE_VARIABLE ||
-		     vrr->state == VRR_STATE_ACTIVE_FIXED;
+
+	if (amdgpu_hdmi_vrr_desktop_mode) {
+		vrr_active = vrr->state != VRR_STATE_UNSUPPORTED &&
+			     vrr->state != VRR_STATE_DISABLED;
+	} else {
+		vrr_active = vrr->state == VRR_STATE_ACTIVE_VARIABLE ||
+			     vrr->state == VRR_STATE_ACTIVE_FIXED;
+	}
 
 	infopacket->sb[VTEM_MD0] = VTEM_M_CONST << VTEM_M_CONST_BIT;
 	infopacket->sb[VTEM_MD0] |= VTEM_FVA_FACTOR << VTEM_FVA_BIT;
-- 
2.52.0