2021-04-29 13:41:50

by Kai-Heng Feng

[permalink] [raw]
Subject: [PATCH] drm/radeon/dpm: Disable sclk switching when two 4K 60Hz monitors are connected

Screen flickers rapidly when two 4K 60Hz monitors are connected to an
Oland card. 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 lead, we found that the issue only occurs when
sclk is too low.

So resolve the issue by disabling sclk switching when there are two
monitors that requires high pixelclock (> 297MHz).

Signed-off-by: Kai-Heng Feng <[email protected]>
---
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 42281fce552e6..56ed5634cebef 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -1549,6 +1549,7 @@ 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 0c1950f4e146f..3861c0b98fcf3 100644
--- a/drivers/gpu/drm/radeon/radeon_pm.c
+++ b/drivers/gpu/drm/radeon/radeon_pm.c
@@ -1767,6 +1767,7 @@ 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;
@@ -1776,6 +1777,7 @@ 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) {
@@ -1783,6 +1785,12 @@ 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 9186095518047..be6fa3257d1bc 100644
--- a/drivers/gpu/drm/radeon/si_dpm.c
+++ b/drivers/gpu/drm/radeon/si_dpm.c
@@ -2995,6 +2995,9 @@ static void si_apply_state_adjust_rules(struct radeon_device *rdev,
ni_dpm_vblank_too_short(rdev))
disable_mclk_switching = true;

+ if (rdev->pm.dpm.high_pixelclock_count > 1)
+ disable_sclk_switching = true;
+
if (rps->vclk || rps->dclk) {
disable_mclk_switching = true;
disable_sclk_switching = true;
--
2.30.2


2021-04-29 21:53:47

by Alex Deucher

[permalink] [raw]
Subject: Re: [PATCH] drm/radeon/dpm: Disable sclk switching when two 4K 60Hz monitors are connected

On Thu, Apr 29, 2021 at 9:40 AM Kai-Heng Feng
<[email protected]> wrote:
>
> Screen flickers rapidly when two 4K 60Hz monitors are connected to an
> Oland card. 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 lead, we found that the issue only occurs when
> sclk is too low.
>
> So resolve the issue by disabling sclk switching when there are two
> monitors that requires high pixelclock (> 297MHz).
>
> Signed-off-by: Kai-Heng Feng <[email protected]>
> ---
> 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 42281fce552e6..56ed5634cebef 100644
> --- a/drivers/gpu/drm/radeon/radeon.h
> +++ b/drivers/gpu/drm/radeon/radeon.h
> @@ -1549,6 +1549,7 @@ 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 0c1950f4e146f..3861c0b98fcf3 100644
> --- a/drivers/gpu/drm/radeon/radeon_pm.c
> +++ b/drivers/gpu/drm/radeon/radeon_pm.c
> @@ -1767,6 +1767,7 @@ 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;
> @@ -1776,6 +1777,7 @@ 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) {
> @@ -1783,6 +1785,12 @@ 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 9186095518047..be6fa3257d1bc 100644
> --- a/drivers/gpu/drm/radeon/si_dpm.c
> +++ b/drivers/gpu/drm/radeon/si_dpm.c
> @@ -2995,6 +2995,9 @@ static void si_apply_state_adjust_rules(struct radeon_device *rdev,
> ni_dpm_vblank_too_short(rdev))
> disable_mclk_switching = true;
>
> + if (rdev->pm.dpm.high_pixelclock_count > 1)
> + disable_sclk_switching = true;
> +

I would suggest limiting this to just Oland.

Alex


> if (rps->vclk || rps->dclk) {
> disable_mclk_switching = true;
> disable_sclk_switching = true;
> --
> 2.30.2
>
> _______________________________________________
> dri-devel mailing list
> [email protected]
> https://lists.freedesktop.org/mailman/listinfo/dri-devel