Commit 382bd6a7 authored by Matthew Schwartz's avatar Matthew Schwartz Committed by Alex Deucher
Browse files

drm/amd/display: Don't program BLNDGAM_MEM_PWR_FORCE when CM low-power is disabled on DCN30 



Before commit 33056a97 ("drm/amd/display: Remove double checks for
`debug.enable_mem_low_power.bits.cm`"), dpp3_program_blnd_lut(NULL)
checked the low-power debug flag before calling
dpp3_power_on_blnd_lut(false).

After commit 33056a97 ("drm/amd/display: Remove double checks for
`debug.enable_mem_low_power.bits.cm`"), dpp3_program_blnd_lut(NULL)
unconditionally calls dpp3_power_on_blnd_lut(false). The BLNDGAM power
helper writes BLNDGAM_MEM_PWR_FORCE when CM low-power is disabled, causing
immediate SRAM power toggles instead of deferring at vupdate. This can
disrupt atomic color/LUT sequencing during transitions between
direct scanout and composition within gamescope's DRM backend on
Steam Deck OLED.

To fix this, leave the BLNDGAM power state unchanged when low-power is
disabled, matching dpp3_power_on_hdr3dlut and dpp3_power_on_shaper.

Fixes: 33056a97 ("drm/amd/display: Remove double checks for `debug.enable_mem_low_power.bits.cm`")
Signed-off-by: default avatarMatthew Schwartz <matthew.schwartz@linux.dev>
Reviewed-by: default avatarHarry Wentland <harry.wentland@amd.com>
Reviewed-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 13ff4f63)
Cc: stable@vger.kernel.org
parent 5d7b36d1

drivers/gpu/drm/amd/display/dc/dpp/dcn30/dcn30_dpp.c

+0 −3
Original line number Diff line number Diff line
@@ -578,9 +578,6 @@ static void dpp3_power_on_blnd_lut( 
			dpp_base->ctx->dc->optimized_required = true;

			dpp_base->deferred_reg_writes.bits.disable_blnd_lut = true;

		}

	} else {

		REG_SET(CM_MEM_PWR_CTRL, 0,

				BLNDGAM_MEM_PWR_FORCE, power_on == true ? 0 : 1);

	}

}