ACK: [PATCH 1/1] drm/radeon/dpm: Disable sclk switching on Oland when two 4K 60Hz monitors are connected

[Stefan Bader]

On 13.05.21 18:26, Kai-Heng Feng wrote:
> BugLink: https://bugs.launchpad.net/bugs/1928361
> 
> Screen flickers rapidly when two 4K 60Hz monitors are in use. This issue
> doesn't happen when one monitor is 4K 60Hz (pixelclock 594MHz) and
> another one is 4K 30Hz (pixelclock 297MHz).
> 
> The issue is gone after setting "power_dpm_force_performance_level" to
> "high". Following the indication, we found that the issue occurs when
> sclk is too low.
> 
> So resolve the issue by disabling sclk switching when there are two
> monitors requires high pixelclock (> 297MHz).
> 
> v2:
>   - Only apply the fix to Oland.
> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> (cherry picked from commit ae30d41eb54eb0926afb82ad5ee4fd3536cce060 linux-next)
> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
Acked-by: Stefan Bader <stefan.bader at canonical.com>
> ---
>   drivers/gpu/drm/radeon/radeon.h    | 1 +
>   drivers/gpu/drm/radeon/radeon_pm.c | 8 ++++++++
>   drivers/gpu/drm/radeon/si_dpm.c    | 3 +++
>   3 files changed, 12 insertions(+)
> 
> diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
> index 3effc8c71494..ea44423376c4 100644
> --- a/drivers/gpu/drm/radeon/radeon.h
> +++ b/drivers/gpu/drm/radeon/radeon.h
> @@ -1558,6 +1558,7 @@ struct radeon_dpm {
>   	void                    *priv;
>   	u32			new_active_crtcs;
>   	int			new_active_crtc_count;
> +	int			high_pixelclock_count;
>   	u32			current_active_crtcs;
>   	int			current_active_crtc_count;
>   	bool single_display;
> diff --git a/drivers/gpu/drm/radeon/radeon_pm.c b/drivers/gpu/drm/radeon/radeon_pm.c
> index 1995dad59dd0..2db4a8b1542d 100644
> --- a/drivers/gpu/drm/radeon/radeon_pm.c
> +++ b/drivers/gpu/drm/radeon/radeon_pm.c
> @@ -1775,6 +1775,7 @@ static void radeon_pm_compute_clocks_dpm(struct radeon_device *rdev)
>   	struct drm_device *ddev = rdev->ddev;
>   	struct drm_crtc *crtc;
>   	struct radeon_crtc *radeon_crtc;
> +	struct radeon_connector *radeon_connector;
>   
>   	if (!rdev->pm.dpm_enabled)
>   		return;
> @@ -1784,6 +1785,7 @@ static void radeon_pm_compute_clocks_dpm(struct radeon_device *rdev)
>   	/* update active crtc counts */
>   	rdev->pm.dpm.new_active_crtcs = 0;
>   	rdev->pm.dpm.new_active_crtc_count = 0;
> +	rdev->pm.dpm.high_pixelclock_count = 0;
>   	if (rdev->num_crtc && rdev->mode_info.mode_config_initialized) {
>   		list_for_each_entry(crtc,
>   				    &ddev->mode_config.crtc_list, head) {
> @@ -1791,6 +1793,12 @@ static void radeon_pm_compute_clocks_dpm(struct radeon_device *rdev)
>   			if (crtc->enabled) {
>   				rdev->pm.dpm.new_active_crtcs |= (1 << radeon_crtc->crtc_id);
>   				rdev->pm.dpm.new_active_crtc_count++;
> +				if (!radeon_crtc->connector)
> +					continue;
> +
> +				radeon_connector = to_radeon_connector(radeon_crtc->connector);
> +				if (radeon_connector->pixelclock_for_modeset > 297000)
> +					rdev->pm.dpm.high_pixelclock_count++;
>   			}
>   		}
>   	}
> diff --git a/drivers/gpu/drm/radeon/si_dpm.c b/drivers/gpu/drm/radeon/si_dpm.c
> index 91bfc4762767..43b63705d073 100644
> --- a/drivers/gpu/drm/radeon/si_dpm.c
> +++ b/drivers/gpu/drm/radeon/si_dpm.c
> @@ -2979,6 +2979,9 @@ static void si_apply_state_adjust_rules(struct radeon_device *rdev,
>   		    (rdev->pdev->device == 0x6605)) {
>   			max_sclk = 75000;
>   		}
> +
> +		if (rdev->pm.dpm.high_pixelclock_count > 1)
> +			disable_sclk_switching = true;
>   	}
>   
>   	if (rps->vce_active) {
> 


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