| Message ID | 20191021194414.24627-1-sunpeng.li@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm/amdgpu: Add DC feature mask to disable fractional pwm | expand |
Reviewed-by: Anthony Koo <anthony.koo@amd.com> -----Original Message----- From: sunpeng.li@amd.com <sunpeng.li@amd.com> Sent: Monday, October 21, 2019 3:44 PM To: amd-gfx@lists.freedesktop.org; dri-devel@lists.freedesktop.org; lskrejci@gmail.com Cc: Koo, Anthony <Anthony.Koo@amd.com>; Wentland, Harry <Harry.Wentland@amd.com>; Li, Sun peng (Leo) <Sunpeng.Li@amd.com> Subject: [PATCH v2] drm/amdgpu: Add DC feature mask to disable fractional pwm From: Leo Li <sunpeng.li@amd.com> [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> --- v2: Add bugzilla link drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 +++ drivers/gpu/drm/amd/display/dc/dce/dce_abm.c | 4 ++++ drivers/gpu/drm/amd/include/amd_shared.h | 1 + 3 files changed, 8 insertions(+) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 1cf4beb76835..73f917d4d1e1 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -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 diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c index d759fdca7fdb..b8a3fc505c9b 100644 --- a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c @@ -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); diff --git a/drivers/gpu/drm/amd/include/amd_shared.h b/drivers/gpu/drm/amd/include/amd_shared.h index 8889aaceec60..5450ed762b7a 100644 --- a/drivers/gpu/drm/amd/include/amd_shared.h +++ b/drivers/gpu/drm/amd/include/amd_shared.h @@ -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, }; enum amd_dpm_forced_level; -- 2.23.0
On Mon, 2019-10-21 at 15:44 -0400, sunpeng.li@amd.com wrote: > From: Leo Li <sunpeng.li@amd.com> > > [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> > --- > > v2: Add bugzilla link > > drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 +++ > drivers/gpu/drm/amd/display/dc/dce/dce_abm.c | 4 ++++ > drivers/gpu/drm/amd/include/amd_shared.h | 1 + > 3 files changed, 8 insertions(+) Tested on Ubuntu 19.04, vanilla v5.3.7 kernel with the patch applied and amdgpu.dcfeaturemask=0x4 added to the kernel command line, no issues after 8 reboots. (The issue could be reproduced without amdgpu.dcfeaturemask=0x4 on first boot.) Tested-by: Lukáš Krejčí <lskrejci@gmail.com>
On 2019-10-23 10:19 a.m., Lukáš Krejčí wrote: > On Mon, 2019-10-21 at 15:44 -0400, sunpeng.li@amd.com wrote: >> From: Leo Li <sunpeng.li@amd.com> >> >> [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> >> --- >> >> v2: Add bugzilla link >> >> drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 3 +++ >> drivers/gpu/drm/amd/display/dc/dce/dce_abm.c | 4 ++++ >> drivers/gpu/drm/amd/include/amd_shared.h | 1 + >> 3 files changed, 8 insertions(+) > > Tested on Ubuntu 19.04, vanilla v5.3.7 kernel with the patch applied > and amdgpu.dcfeaturemask=0x4 added to the kernel command line, no > issues after 8 reboots. (The issue could be reproduced without > amdgpu.dcfeaturemask=0x4 on first boot.) > > Tested-by: Lukáš Krejčí <lskrejci@gmail.com> Applied, thanks! Leo
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 1cf4beb76835..73f917d4d1e1 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -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 diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c index d759fdca7fdb..b8a3fc505c9b 100644 --- a/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_abm.c @@ -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); diff --git a/drivers/gpu/drm/amd/include/amd_shared.h b/drivers/gpu/drm/amd/include/amd_shared.h index 8889aaceec60..5450ed762b7a 100644 --- a/drivers/gpu/drm/amd/include/amd_shared.h +++ b/drivers/gpu/drm/amd/include/amd_shared.h @@ -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, }; enum amd_dpm_forced_level;