Patch "drm/amd/display: Adjust DCE 8-10 clock, don't overclock by 15%" has been added to the 6.12-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    drm/amd/display: Adjust DCE 8-10 clock, don't overclock by 15%

to the 6.12-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-amd-display-adjust-dce-8-10-clock-don-t-overclock-by-15.patch
and it can be found in the queue-6.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From stable+bounces-232627-greg=kroah.com@vger.kernel.org Wed Apr  1 02:45:17 2026
From: Rosen Penev <rosenp@gmail.com>
Date: Tue, 31 Mar 2026 17:39:05 -0700
Subject: drm/amd/display: Adjust DCE 8-10 clock, don't overclock by 15%
To: stable@vger.kernel.org
Cc: "Alex Deucher" <alexander.deucher@amd.com>, "Christian König" <christian.koenig@amd.com>, "Xinhui Pan" <Xinhui.Pan@amd.com>, "David Airlie" <airlied@gmail.com>, "Simona Vetter" <simona@ffwll.ch>, "Harry Wentland" <harry.wentland@amd.com>, "Leo Li" <sunpeng.li@amd.com>, "Rodrigo Siqueira" <Rodrigo.Siqueira@amd.com>, "Ray Wu" <ray.wu@amd.com>, "Wayne Lin" <wayne.lin@amd.com>, "Mario Limonciello" <Mario.Limonciello@amd.com>, "Roman Li" <Roman.Li@amd.com>, "Eric Yang" <Eric.Yang2@amd.com>, "Tony Cheng" <Tony.Cheng@amd.com>, "Mauro Rossi" <issor.oruam@gmail.com>, "Timur Kristóf" <timur.kristof@gmail.com>, "Alex Hung" <alex.hung@amd.com>, amd-gfx@lists.freedesktop.org (open list:RADEON and AMDGPU DRM DRIVERS), dri-devel@lists.freedesktop.org (open list:DRM DRIVERS), linux-kernel@vger.kernel.org (open list)
Message-ID: <20260401003908.3438-8-rosenp@gmail.com>

From: Timur Kristóf <timur.kristof@gmail.com>

[ Upstream commit 1ae45b5d4f371af8ae51a3827d0ec9fe27eeb867 ]

Adjust the nominal (and performance) clocks for DCE 8-10,
and set them to 625 MHz, which is the value used by the legacy
display code in amdgpu_atombios_get_clock_info.

This was tested with Hawaii, Tonga and Fiji.
These GPUs can output 4K 60Hz (10-bit depth) at 625 MHz.

The extra 15% clock was added as a workaround for a Polaris issue
which uses DCE 11, and should not have been used on DCE 8-10 which
are already hardcoded to the highest possible display clock.
Unfortunately, the extra 15% was mistakenly copied and kept
even on code paths which don't affect Polaris.

This commit fixes that and also	adds a check to	make sure
not to exceed the maximum DCE 8-10 display clock.

Fixes: 8cd61c313d8b ("drm/amd/display: Raise dispclk value for Polaris")
Fixes: dc88b4a684d2 ("drm/amd/display: make clk mgr soc specific")
Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Rodrigo Siqueira <siqueira@igalia.com>
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Rosen Penev <rosenp@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/amd/display/dc/clk_mgr/dce100/dce_clk_mgr.c |   12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

--- a/drivers/gpu/drm/amd/display/dc/clk_mgr/dce100/dce_clk_mgr.c
+++ b/drivers/gpu/drm/amd/display/dc/clk_mgr/dce100/dce_clk_mgr.c
@@ -72,9 +72,9 @@ static const struct state_dependent_cloc
 /* ClocksStateLow */
 { .display_clk_khz = 352000, .pixel_clk_khz = 330000},
 /* ClocksStateNominal */
-{ .display_clk_khz = 600000, .pixel_clk_khz = 400000 },
+{ .display_clk_khz = 625000, .pixel_clk_khz = 400000 },
 /* ClocksStatePerformance */
-{ .display_clk_khz = 600000, .pixel_clk_khz = 400000 } };
+{ .display_clk_khz = 625000, .pixel_clk_khz = 400000 } };
 
 int dentist_get_divider_from_did(int did)
 {
@@ -403,11 +403,9 @@ static void dce_update_clocks(struct clk
 {
 	struct clk_mgr_internal *clk_mgr_dce = TO_CLK_MGR_INTERNAL(clk_mgr_base);
 	struct dm_pp_power_level_change_request level_change_req;
-	int patched_disp_clk = context->bw_ctx.bw.dce.dispclk_khz;
-
-	/*TODO: W/A for dal3 linux, investigate why this works */
-	if (!clk_mgr_dce->dfs_bypass_active)
-		patched_disp_clk = patched_disp_clk * 115 / 100;
+	const int max_disp_clk =
+		clk_mgr_dce->max_clks_by_state[DM_PP_CLOCKS_STATE_PERFORMANCE].display_clk_khz;
+	int patched_disp_clk = MIN(max_disp_clk, context->bw_ctx.bw.dce.dispclk_khz);
 
 	level_change_req.power_level = dce_get_required_clocks_state(clk_mgr_base, context);
 	/* get max clock state from PPLIB */


Patches currently in stable-queue which might be from rosenp@gmail.com are

queue-6.12/drm-amd-amdgpu-decouple-aspm-with-pcie-dpm.patch
queue-6.12/drm-amd-display-reject-modes-with-too-high-pixel-clock-on-dce6-10.patch
queue-6.12/drm-amd-display-fix-dce-6.0-and-6.4-pll-programming.patch
queue-6.12/drm-amd-display-disable-scaling-on-dce6-for-now.patch
queue-6.12/drm-amd-display-disable-fastboot-on-dce-6-too.patch
queue-6.12/drm-amd-display-correct-logic-check-error-for-fastboot.patch
queue-6.12/drm-amd-amdgpu-disable-aspm-in-some-situations.patch
queue-6.12/drm-amd-display-keep-pll0-running-on-dce-6.0-and-6.4.patch
queue-6.12/drm-amd-display-adjust-dce-8-10-clock-don-t-overclock-by-15.patch
queue-6.12/drm-amd-disable-aspm-on-si.patch