drm/amdgpu: Add DC feature mask to disable fractional pwm (eaf56410) · Commits · 戴 / test

[Why] Some LED panel drivers might not like fractional PWM. In such cases, backlight flickering may be observed. [How] Add a DC feature mask to disable fractional PWM, and associate it with the preexisting dc_config flag. The flag is only plumbed through the dmcu firmware, so plumb it through the driver path as well. To disable, add the following to the linux cmdline: amdgpu.dcfeaturemask=0x4 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204957 Signed-off-by:

Leo Li <sunpeng.li@amd.com> Reviewed-by:

Anthony Koo <anthony.koo@amd.com> Tested-by:

Lukáš Krejčí <lskrejci@gmail.com> Signed-off-by:

Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -728,6 +728,9 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
		if (amdgpu_dc_feature_mask & DC_MULTI_MON_PP_MCLK_SWITCH_MASK)
		init_data.flags.multi_mon_pp_mclk_switch = true;

		if (amdgpu_dc_feature_mask & DC_DISABLE_FRACTIONAL_PWM_MASK)
		init_data.flags.disable_fractional_pwm = true;

		init_data.flags.power_down_display_on_boot = true;

		#ifdef CONFIG_DRM_AMD_DC_DCN2_0

drivers/gpu/drm/amd/display/dc/dce/dce_abm.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -404,6 +404,10 @@ static bool dce_abm_init_backlight(struct abm *abm)
		/* Enable the backlight output */
		REG_UPDATE(BL_PWM_CNTL, BL_PWM_EN, 1);

		/* Disable fractional pwm if configured */
		REG_UPDATE(BL_PWM_CNTL, BL_PWM_FRACTIONAL_EN,
		abm->ctx->dc->config.disable_fractional_pwm ? 0 : 1);

		/* Unlock group 2 backlight registers */
		REG_UPDATE(BL_PWM_GRP1_REG_LOCK,
		BL_PWM_GRP1_REG_LOCK, 0);

drivers/gpu/drm/amd/include/amd_shared.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -143,6 +143,7 @@ enum PP_FEATURE_MASK {
		enum DC_FEATURE_MASK {
		DC_FBC_MASK = 0x1,
		DC_MULTI_MON_PP_MCLK_SWITCH_MASK = 0x2,
		DC_DISABLE_FRACTIONAL_PWM_MASK = 0x4,
		DC_PSR_MASK = 0x8,
		};

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