diff mbox series

[v10,15/24] drm/mediatek: Remove ineffectual power management codes

Message ID 20231019055619.19358-16-shawn.sung@mediatek.com
State New
Headers
Series Add display driver for MT8188 VDOSYS1 |

Commit Message

Shawn Sung (宋孝謙) Oct. 19, 2023, 5:56 a.m. UTC 
  Display modules will be powered on when .atomic_enable(),
there is no need to do it again in mtk_crtc_ddp_hw_init().
Besides, the DRM devices are created manually when mtk-mmsys
is probed and there is no power domain linked to it.

Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")

Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

Comments

AngeloGioacchino Del Regno Oct. 19, 2023, 9:07 a.m. UTC | #1 
Il 19/10/23 07:56, Hsiao Chien Sung ha scritto:
> Display modules will be powered on when .atomic_enable(),
> there is no need to do it again in mtk_crtc_ddp_hw_init().
> Besides, the DRM devices are created manually when mtk-mmsys
> is probed and there is no power domain linked to it.
> 
> Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
> 
> Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
> ---
>   drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 18 +++---------------
>   1 file changed, 3 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> index bc4cc75cca18..c7edd80be428 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> @@ -6,7 +6,6 @@
>   #include <linux/clk.h>
>   #include <linux/dma-mapping.h>
>   #include <linux/mailbox_controller.h>
> -#include <linux/pm_runtime.h>
>   #include <linux/soc/mediatek/mtk-cmdq.h>
>   #include <linux/soc/mediatek/mtk-mmsys.h>
>   #include <linux/soc/mediatek/mtk-mutex.h>
> @@ -362,22 +361,16 @@ static int mtk_crtc_ddp_hw_init(struct mtk_drm_crtc *mtk_crtc, struct drm_atomic
>   		drm_connector_list_iter_end(&conn_iter);
>   	}
>   
> -	ret = pm_runtime_resume_and_get(crtc->dev->dev);
> -	if (ret < 0) {
> -		DRM_ERROR("Failed to enable power domain: %d\n", ret);
> -		return ret;
> -	}
> -

Are you really sure that writes to DISP_REG_OVL_xxx and others in other modules,
called by the .layer_config() callback, can be successfully done on an unpowered
and/or unclocked module, on all MediaTek SoCs?
This looks a bit odd.

>   	ret = mtk_mutex_prepare(mtk_crtc->mutex);
>   	if (ret < 0) {
>   		DRM_ERROR("Failed to enable mutex clock: %d\n", ret);
> -		goto err_pm_runtime_put;
> +		goto error;
>   	}
>   
>   	ret = mtk_crtc_ddp_clk_enable(mtk_crtc);
>   	if (ret < 0) {
>   		DRM_ERROR("Failed to enable component clocks: %d\n", ret);
> -		goto err_mutex_unprepare;
> +		goto error;
>   	}
>   
>   	for (i = 0; i < mtk_crtc->ddp_comp_nr - 1; i++) {
> @@ -426,16 +419,13 @@ static int mtk_crtc_ddp_hw_init(struct mtk_drm_crtc *mtk_crtc, struct drm_atomic
>   

...because you could otherwise just call pm_runtime_put() here, instead of removing
the pm_runtime_resume_and_get() call, which is something I would advise to do.

Regards,
Angelo

>   	return 0;
>   
> -err_mutex_unprepare:
> +error:
>   	mtk_mutex_unprepare(mtk_crtc->mutex);
> -err_pm_runtime_put:
> -	pm_runtime_put(crtc->dev->dev);
>   	return ret;
>   }
>   
>   static void mtk_crtc_ddp_hw_fini(struct mtk_drm_crtc *mtk_crtc)
>   {
> -	struct drm_device *drm = mtk_crtc->base.dev;
>   	struct drm_crtc *crtc = &mtk_crtc->base;
>   	int i;
>   
> @@ -465,8 +455,6 @@ static void mtk_crtc_ddp_hw_fini(struct mtk_drm_crtc *mtk_crtc)
>   	mtk_crtc_ddp_clk_disable(mtk_crtc);
>   	mtk_mutex_unprepare(mtk_crtc->mutex);
>   
> -	pm_runtime_put(drm->dev);
> -
>   	if (crtc->state->event && !crtc->state->active) {
>   		spin_lock_irq(&crtc->dev->event_lock);
>   		drm_crtc_send_vblank_event(crtc, crtc->state->event);
Shawn Sung (宋孝謙) Oct. 19, 2023, 9:52 a.m. UTC | #2 
Hi Angelo,

On Thu, 2023-10-19 at 11:07 +0200, AngeloGioacchino Del Regno wrote:
> Il 19/10/23 07:56, Hsiao Chien Sung ha scritto:
> > Display modules will be powered on when .atomic_enable(),
> > there is no need to do it again in mtk_crtc_ddp_hw_init().
> > Besides, the DRM devices are created manually when mtk-mmsys
> > is probed and there is no power domain linked to it.
> > 
> > Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC
> > MT8173.")
> > 
> > Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
> > ---
> >   drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 18 +++---------------
> >   1 file changed, 3 insertions(+), 15 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > index bc4cc75cca18..c7edd80be428 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > @@ -6,7 +6,6 @@
> >   #include <linux/clk.h>
> >   #include <linux/dma-mapping.h>
> >   #include <linux/mailbox_controller.h>
> > -#include <linux/pm_runtime.h>
> >   #include <linux/soc/mediatek/mtk-cmdq.h>
> >   #include <linux/soc/mediatek/mtk-mmsys.h>
> >   #include <linux/soc/mediatek/mtk-mutex.h>
> > @@ -362,22 +361,16 @@ static int mtk_crtc_ddp_hw_init(struct
> > mtk_drm_crtc *mtk_crtc, struct drm_atomic
> >   		drm_connector_list_iter_end(&conn_iter);
> >   	}
> >   
> > -	ret = pm_runtime_resume_and_get(crtc->dev->dev);
> > -	if (ret < 0) {
> > -		DRM_ERROR("Failed to enable power domain: %d\n", ret);
> > -		return ret;
> > -	}
> > -
> 
> Are you really sure that writes to DISP_REG_OVL_xxx and others in
> other modules,
> called by the .layer_config() callback, can be successfully done on
> an unpowered
> and/or unclocked module, on all MediaTek SoCs?
> This looks a bit odd.

Not sure if I get your point correctly. We removed this PM API because:

1. mtk_crtc_ddp_hw_init() is called by mtk_drm_crtc_atomic_enable(),
and the new inline function mtk_ddp_comp_power_on() is called before hw
init, we can make sure the power is on before configuring the hardware.

2. The device "crtc->dev->dev" here is assigned by the probe function
of mtk-mmsys, which will be look like "mediatek-drm.auto.13", and this
device is not linked to any power domain.

> 
> >   	ret = mtk_mutex_prepare(mtk_crtc->mutex);
> >   	if (ret < 0) {
> >   		DRM_ERROR("Failed to enable mutex clock: %d\n", ret);
> > -		goto err_pm_runtime_put;
> > +		goto error;
> >   	}
> >   
> >   	ret = mtk_crtc_ddp_clk_enable(mtk_crtc);
> >   	if (ret < 0) {
> >   		DRM_ERROR("Failed to enable component clocks: %d\n",
> > ret);
> > -		goto err_mutex_unprepare;
> > +		goto error;
> >   	}
> >   
> >   	for (i = 0; i < mtk_crtc->ddp_comp_nr - 1; i++) {
> > @@ -426,16 +419,13 @@ static int mtk_crtc_ddp_hw_init(struct
> > mtk_drm_crtc *mtk_crtc, struct drm_atomic
> >   
> 
> ...because you could otherwise just call pm_runtime_put() here,
> instead of removing
> the pm_runtime_resume_and_get() call, which is something I would
> advise to do.
> 
> Regards,
> Angelo
> 

Thanks,
Shawn
AngeloGioacchino Del Regno Oct. 19, 2023, 10:17 a.m. UTC | #3 
Il 19/10/23 11:52, Shawn Sung (宋孝謙) ha scritto:
> Hi Angelo,
> 
> On Thu, 2023-10-19 at 11:07 +0200, AngeloGioacchino Del Regno wrote:
>> Il 19/10/23 07:56, Hsiao Chien Sung ha scritto:
>>> Display modules will be powered on when .atomic_enable(),
>>> there is no need to do it again in mtk_crtc_ddp_hw_init().
>>> Besides, the DRM devices are created manually when mtk-mmsys
>>> is probed and there is no power domain linked to it.
>>>
>>> Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC
>>> MT8173.")
>>>
>>> Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
>>> ---
>>>    drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 18 +++---------------
>>>    1 file changed, 3 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
>>> b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
>>> index bc4cc75cca18..c7edd80be428 100644
>>> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
>>> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
>>> @@ -6,7 +6,6 @@
>>>    #include <linux/clk.h>
>>>    #include <linux/dma-mapping.h>
>>>    #include <linux/mailbox_controller.h>
>>> -#include <linux/pm_runtime.h>
>>>    #include <linux/soc/mediatek/mtk-cmdq.h>
>>>    #include <linux/soc/mediatek/mtk-mmsys.h>
>>>    #include <linux/soc/mediatek/mtk-mutex.h>
>>> @@ -362,22 +361,16 @@ static int mtk_crtc_ddp_hw_init(struct
>>> mtk_drm_crtc *mtk_crtc, struct drm_atomic
>>>    		drm_connector_list_iter_end(&conn_iter);
>>>    	}
>>>    
>>> -	ret = pm_runtime_resume_and_get(crtc->dev->dev);
>>> -	if (ret < 0) {
>>> -		DRM_ERROR("Failed to enable power domain: %d\n", ret);
>>> -		return ret;
>>> -	}
>>> -
>>
>> Are you really sure that writes to DISP_REG_OVL_xxx and others in
>> other modules,
>> called by the .layer_config() callback, can be successfully done on
>> an unpowered
>> and/or unclocked module, on all MediaTek SoCs?
>> This looks a bit odd.
> 
> Not sure if I get your point correctly. We removed this PM API because:
> 
> 1. mtk_crtc_ddp_hw_init() is called by mtk_drm_crtc_atomic_enable(),
> and the new inline function mtk_ddp_comp_power_on() is called before hw
> init, we can make sure the power is on before configuring the hardware.
> 
> 2. The device "crtc->dev->dev" here is assigned by the probe function
> of mtk-mmsys, which will be look like "mediatek-drm.auto.13", and this
> device is not linked to any power domain.
> 

Thanks for the clarification. In this case:

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

>>
>>>    	ret = mtk_mutex_prepare(mtk_crtc->mutex);
>>>    	if (ret < 0) {
>>>    		DRM_ERROR("Failed to enable mutex clock: %d\n", ret);
>>> -		goto err_pm_runtime_put;
>>> +		goto error;
>>>    	}
>>>    
>>>    	ret = mtk_crtc_ddp_clk_enable(mtk_crtc);
>>>    	if (ret < 0) {
>>>    		DRM_ERROR("Failed to enable component clocks: %d\n",
>>> ret);
>>> -		goto err_mutex_unprepare;
>>> +		goto error;
>>>    	}
>>>    
>>>    	for (i = 0; i < mtk_crtc->ddp_comp_nr - 1; i++) {
>>> @@ -426,16 +419,13 @@ static int mtk_crtc_ddp_hw_init(struct
>>> mtk_drm_crtc *mtk_crtc, struct drm_atomic
>>>    
>>
>> ...because you could otherwise just call pm_runtime_put() here,
>> instead of removing
>> the pm_runtime_resume_and_get() call, which is something I would
>> advise to do.
>>
>> Regards,
>> Angelo
>>
> 
> Thanks,
> Shawn
CK Hu (胡俊光) Oct. 24, 2023, 9:25 a.m. UTC | #4 
Hi, Hsiao-chien:

On Thu, 2023-10-19 at 13:56 +0800, Hsiao Chien Sung wrote:
> Display modules will be powered on when .atomic_enable(),
> there is no need to do it again in mtk_crtc_ddp_hw_init().
> Besides, the DRM devices are created manually when mtk-mmsys
> is probed and there is no power domain linked to it.
> 
> Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC
> MT8173.")
> 
> Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 18 +++---------------
>  1 file changed, 3 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> index bc4cc75cca18..c7edd80be428 100644
> --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> @@ -6,7 +6,6 @@
>  #include <linux/clk.h>
>  #include <linux/dma-mapping.h>
>  #include <linux/mailbox_controller.h>
> -#include <linux/pm_runtime.h>
>  #include <linux/soc/mediatek/mtk-cmdq.h>
>  #include <linux/soc/mediatek/mtk-mmsys.h>
>  #include <linux/soc/mediatek/mtk-mutex.h>
> @@ -362,22 +361,16 @@ static int mtk_crtc_ddp_hw_init(struct
> mtk_drm_crtc *mtk_crtc, struct drm_atomic
>  		drm_connector_list_iter_end(&conn_iter);
>  	}
>  
> -	ret = pm_runtime_resume_and_get(crtc->dev->dev);

crtc->dev->dev is mmsys device. In mt8173.dtsi, you could find that
mmsys has its own power. So I think we should keep this.

Regards,
CK

> -	if (ret < 0) {
> -		DRM_ERROR("Failed to enable power domain: %d\n", ret);
> -		return ret;
> -	}
> -
>  	ret = mtk_mutex_prepare(mtk_crtc->mutex);
>  	if (ret < 0) {
>  		DRM_ERROR("Failed to enable mutex clock: %d\n", ret);
> -		goto err_pm_runtime_put;
> +		goto error;
>  	}
>  
>  	ret = mtk_crtc_ddp_clk_enable(mtk_crtc);
>  	if (ret < 0) {
>  		DRM_ERROR("Failed to enable component clocks: %d\n",
> ret);
> -		goto err_mutex_unprepare;
> +		goto error;
>  	}
>  
>  	for (i = 0; i < mtk_crtc->ddp_comp_nr - 1; i++) {
> @@ -426,16 +419,13 @@ static int mtk_crtc_ddp_hw_init(struct
> mtk_drm_crtc *mtk_crtc, struct drm_atomic
>  
>  	return 0;
>  
> -err_mutex_unprepare:
> +error:
>  	mtk_mutex_unprepare(mtk_crtc->mutex);
> -err_pm_runtime_put:
> -	pm_runtime_put(crtc->dev->dev);
>  	return ret;
>  }
>  
>  static void mtk_crtc_ddp_hw_fini(struct mtk_drm_crtc *mtk_crtc)
>  {
> -	struct drm_device *drm = mtk_crtc->base.dev;
>  	struct drm_crtc *crtc = &mtk_crtc->base;
>  	int i;
>  
> @@ -465,8 +455,6 @@ static void mtk_crtc_ddp_hw_fini(struct
> mtk_drm_crtc *mtk_crtc)
>  	mtk_crtc_ddp_clk_disable(mtk_crtc);
>  	mtk_mutex_unprepare(mtk_crtc->mutex);
>  
> -	pm_runtime_put(drm->dev);
> -
>  	if (crtc->state->event && !crtc->state->active) {
>  		spin_lock_irq(&crtc->dev->event_lock);
>  		drm_crtc_send_vblank_event(crtc, crtc->state->event);
Shawn Sung (宋孝謙) Oct. 24, 2023, 9:39 a.m. UTC | #5 
Hi CK,

On Tue, 2023-10-24 at 09:25 +0000, CK Hu (胡俊光) wrote:
> Hi, Hsiao-chien:
> 
> On Thu, 2023-10-19 at 13:56 +0800, Hsiao Chien Sung wrote:
> > Display modules will be powered on when .atomic_enable(),
> > there is no need to do it again in mtk_crtc_ddp_hw_init().
> > Besides, the DRM devices are created manually when mtk-mmsys
> > is probed and there is no power domain linked to it.
> > 
> > Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC
> > MT8173.")
> > 
> > Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
> > ---
> >  drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 18 +++---------------
> >  1 file changed, 3 insertions(+), 15 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > index bc4cc75cca18..c7edd80be428 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
> > @@ -6,7 +6,6 @@
> >  #include <linux/clk.h>
> >  #include <linux/dma-mapping.h>
> >  #include <linux/mailbox_controller.h>
> > -#include <linux/pm_runtime.h>
> >  #include <linux/soc/mediatek/mtk-cmdq.h>
> >  #include <linux/soc/mediatek/mtk-mmsys.h>
> >  #include <linux/soc/mediatek/mtk-mutex.h>
> > @@ -362,22 +361,16 @@ static int mtk_crtc_ddp_hw_init(struct
> > mtk_drm_crtc *mtk_crtc, struct drm_atomic
> >  		drm_connector_list_iter_end(&conn_iter);
> >  	}
> >  
> > -	ret = pm_runtime_resume_and_get(crtc->dev->dev);
> 
> crtc->dev->dev is mmsys device. In mt8173.dtsi, you could find that
> mmsys has its own power. So I think we should keep this.
> 
> Regards,
> CK

Didn't notice this difference in the dts, thank you for checking.
Will remove this patch in the next version.

Thanks,
Shawn
diff mbox series

Patch

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
index bc4cc75cca18..c7edd80be428 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
@@ -6,7 +6,6 @@ 
 #include <linux/clk.h>
 #include <linux/dma-mapping.h>
 #include <linux/mailbox_controller.h>
-#include <linux/pm_runtime.h>
 #include <linux/soc/mediatek/mtk-cmdq.h>
 #include <linux/soc/mediatek/mtk-mmsys.h>
 #include <linux/soc/mediatek/mtk-mutex.h>
@@ -362,22 +361,16 @@  static int mtk_crtc_ddp_hw_init(struct mtk_drm_crtc *mtk_crtc, struct drm_atomic
 		drm_connector_list_iter_end(&conn_iter);
 	}
 
-	ret = pm_runtime_resume_and_get(crtc->dev->dev);
-	if (ret < 0) {
-		DRM_ERROR("Failed to enable power domain: %d\n", ret);
-		return ret;
-	}
-
 	ret = mtk_mutex_prepare(mtk_crtc->mutex);
 	if (ret < 0) {
 		DRM_ERROR("Failed to enable mutex clock: %d\n", ret);
-		goto err_pm_runtime_put;
+		goto error;
 	}
 
 	ret = mtk_crtc_ddp_clk_enable(mtk_crtc);
 	if (ret < 0) {
 		DRM_ERROR("Failed to enable component clocks: %d\n", ret);
-		goto err_mutex_unprepare;
+		goto error;
 	}
 
 	for (i = 0; i < mtk_crtc->ddp_comp_nr - 1; i++) {
@@ -426,16 +419,13 @@  static int mtk_crtc_ddp_hw_init(struct mtk_drm_crtc *mtk_crtc, struct drm_atomic
 
 	return 0;
 
-err_mutex_unprepare:
+error:
 	mtk_mutex_unprepare(mtk_crtc->mutex);
-err_pm_runtime_put:
-	pm_runtime_put(crtc->dev->dev);
 	return ret;
 }
 
 static void mtk_crtc_ddp_hw_fini(struct mtk_drm_crtc *mtk_crtc)
 {
-	struct drm_device *drm = mtk_crtc->base.dev;
 	struct drm_crtc *crtc = &mtk_crtc->base;
 	int i;
 
@@ -465,8 +455,6 @@  static void mtk_crtc_ddp_hw_fini(struct mtk_drm_crtc *mtk_crtc)
 	mtk_crtc_ddp_clk_disable(mtk_crtc);
 	mtk_mutex_unprepare(mtk_crtc->mutex);
 
-	pm_runtime_put(drm->dev);
-
 	if (crtc->state->event && !crtc->state->active) {
 		spin_lock_irq(&crtc->dev->event_lock);
 		drm_crtc_send_vblank_event(crtc, crtc->state->event);