git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 382bd6a792836875da555fe9a2b51222b813fed1 Mon Sep 17 00:00:00 2001
   2 From: Matthew Schwartz <matthew.schwartz@linux.dev>
   3 Date: Mon, 20 Oct 2025 16:09:34 -0700
   4 Subject: drm/amd/display: Don't program BLNDGAM_MEM_PWR_FORCE when CM low-power is disabled on DCN30
   5
   6 From: Matthew Schwartz <matthew.schwartz@linux.dev>
   7
   8 commit 382bd6a792836875da555fe9a2b51222b813fed1 upstream.
   9
  10 Before commit 33056a97ae5e ("drm/amd/display: Remove double checks for
  11 `debug.enable_mem_low_power.bits.cm`"), dpp3_program_blnd_lut(NULL)
  12 checked the low-power debug flag before calling
  13 dpp3_power_on_blnd_lut(false).
  14
  15 After commit 33056a97ae5e ("drm/amd/display: Remove double checks for
  16 `debug.enable_mem_low_power.bits.cm`"), dpp3_program_blnd_lut(NULL)
  17 unconditionally calls dpp3_power_on_blnd_lut(false). The BLNDGAM power
  18 helper writes BLNDGAM_MEM_PWR_FORCE when CM low-power is disabled, causing
  19 immediate SRAM power toggles instead of deferring at vupdate. This can
  20 disrupt atomic color/LUT sequencing during transitions between
  21 direct scanout and composition within gamescope's DRM backend on
  22 Steam Deck OLED.
  23
  24 To fix this, leave the BLNDGAM power state unchanged when low-power is
  25 disabled, matching dpp3_power_on_hdr3dlut and dpp3_power_on_shaper.
  26
  27 Fixes: 33056a97ae5e ("drm/amd/display: Remove double checks for `debug.enable_mem_low_power.bits.cm`")
  28 Signed-off-by: Matthew Schwartz <matthew.schwartz@linux.dev>
  29 Reviewed-by: Harry Wentland <harry.wentland@amd.com>
  30 Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
  31 Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
  32 Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
  33 (cherry picked from commit 13ff4f63fcddfc84ec8632f1443936b00aa26725)
  34 Cc: stable@vger.kernel.org
  35 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  36 ---
  37  drivers/gpu/drm/amd/display/dc/dpp/dcn30/dcn30_dpp.c | 3 ---
  38  1 file changed, 3 deletions(-)
  39
  40 diff --git a/drivers/gpu/drm/amd/display/dc/dpp/dcn30/dcn30_dpp.c b/drivers/gpu/drm/amd/display/dc/dpp/dcn30/dcn30_dpp.c
  41 index 09be2a90cc79..4f569cd8a5d6 100644
  42 --- a/drivers/gpu/drm/amd/display/dc/dpp/dcn30/dcn30_dpp.c
  43 +++ b/drivers/gpu/drm/amd/display/dc/dpp/dcn30/dcn30_dpp.c
  44 @@ -578,9 +578,6 @@ static void dpp3_power_on_blnd_lut(
  45                         dpp_base->ctx->dc->optimized_required = true;
  46                         dpp_base->deferred_reg_writes.bits.disable_blnd_lut = true;
  47                 }
  48 -       } else {
  49 -               REG_SET(CM_MEM_PWR_CTRL, 0,
  50 -                               BLNDGAM_MEM_PWR_FORCE, power_on == true ? 0 : 1);
  51         }
  52  }
  53
  54 --
  55 2.51.2
  56