2023-10-19 05:57:27

by Shawn Sung

[permalink] [raw]
Subject: [PATCH v10 15/24] drm/mediatek: Remove ineffectual power management codes

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 <[email protected]>
---
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;
- }
-
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);
--
2.18.0


Subject: Re: [PATCH v10 15/24] drm/mediatek: Remove ineffectual power management codes

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 <[email protected]>
> ---
> 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);


2023-10-19 09:52:38

by Shawn Sung

[permalink] [raw]
Subject: Re: [PATCH v10 15/24] drm/mediatek: Remove ineffectual power management codes

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 <[email protected]>
> > ---
> > 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

Subject: Re: [PATCH v10 15/24] drm/mediatek: Remove ineffectual power management codes

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 <[email protected]>
>>> ---
>>> 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 <[email protected]>

>>
>>> 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


2023-10-24 09:27:16

by CK Hu (胡俊光)

[permalink] [raw]
Subject: Re: [PATCH v10 15/24] drm/mediatek: Remove ineffectual power management codes

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 <[email protected]>
> ---
> 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);

2023-10-24 09:41:12

by Shawn Sung

[permalink] [raw]
Subject: Re: [PATCH v10 15/24] drm/mediatek: Remove ineffectual power management codes

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 <[email protected]>
> > ---
> > 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