diff mbox series

[v5,2/6] drm: lcdif: Drop unnecessary NULL pointer check on lcdif->bridge

Message ID 20230508055740.635256-3-victor.liu@nxp.com
State New
Headers
Series drm: lcdif: Add i.MX93 LCDIF support |

Commit Message

Liu Ying May 8, 2023, 5:57 a.m. UTC 
  A valid bridge is already found in lcdif_attach_bridge() and set
to lcdif->bridge, so lcdif->bridge cannot be a NULL pointer. Drop
the unnecessary NULL pointer check in KMS stage.

Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
---
v4->v5:
* Add Alexander's T-b tag.

v3->v4:
* Add Alexander's R-b tag.

v2->v3:
* No change.

v1->v2:
* Split from patch 2/2 in v1. (Marek, Alexander)

 drivers/gpu/drm/mxsfb/lcdif_kms.c | 33 +++++++++++--------------------
 1 file changed, 12 insertions(+), 21 deletions(-)

Comments

Marek Vasut May 9, 2023, 12:02 a.m. UTC | #1 
On 5/8/23 07:57, Liu Ying wrote:

Hi,

> diff --git a/drivers/gpu/drm/mxsfb/lcdif_kms.c b/drivers/gpu/drm/mxsfb/lcdif_kms.c
> index 262bc43b1079..e54200a9fcb9 100644
> --- a/drivers/gpu/drm/mxsfb/lcdif_kms.c
> +++ b/drivers/gpu/drm/mxsfb/lcdif_kms.c
> @@ -394,7 +394,7 @@ static void lcdif_crtc_mode_set_nofb(struct lcdif_drm_private *lcdif,
>   	struct drm_display_mode *m = &lcdif->crtc.state->adjusted_mode;
>   	u32 bus_flags = 0;
>   
> -	if (lcdif->bridge && lcdif->bridge->timings)
> +	if (lcdif->bridge->timings)
>   		bus_flags = lcdif->bridge->timings->input_bus_flags;
>   	else if (bridge_state)
>   		bus_flags = bridge_state->input_bus_cfg.flags;
> @@ -463,30 +463,21 @@ static void lcdif_crtc_atomic_enable(struct drm_crtc *crtc,
>   	struct drm_display_mode *m = &lcdif->crtc.state->adjusted_mode;
>   	struct drm_bridge_state *bridge_state = NULL;
>   	struct drm_device *drm = lcdif->drm;
> -	u32 bus_format = 0;
> +	u32 bus_format;
>   	dma_addr_t paddr;
>   
> -	/* If there is a bridge attached to the LCDIF, use its bus format */
> -	if (lcdif->bridge) {
> -		bridge_state =
> -			drm_atomic_get_new_bridge_state(state,
> -							lcdif->bridge);
> -		if (!bridge_state)
> -			bus_format = MEDIA_BUS_FMT_FIXED;
> -		else
> -			bus_format = bridge_state->input_bus_cfg.format;
> -
> -		if (bus_format == MEDIA_BUS_FMT_FIXED) {
> -			dev_warn_once(drm->dev,
> -				      "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
> -				      "Please fix bridge driver by handling atomic_get_input_bus_fmts.\n");
> -			bus_format = MEDIA_BUS_FMT_RGB888_1X24;
> -		}
> -	}
> +	bridge_state = drm_atomic_get_new_bridge_state(state, lcdif->bridge);
> +	if (!bridge_state)
> +		bus_format = MEDIA_BUS_FMT_FIXED;
> +	else
> +		bus_format = bridge_state->input_bus_cfg.format;

The code below seems to change the logic slightly.

Could it happen that:
- bridge_state is valid (i.e. non-NULL)
- bridge_state->input_bus_cfg.format is set to 0 (i.e. not set) ?
   (note that MEDIA_BUS_FMT_FIXED is defined as 0x0001)

> -	/* If all else fails, default to RGB888_1X24 */
> -	if (!bus_format)
> +	if (bus_format == MEDIA_BUS_FMT_FIXED) {
> +		dev_warn_once(drm->dev,
> +			      "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
> +			      "Please fix bridge driver by handling atomic_get_input_bus_fmts.\n");
>   		bus_format = MEDIA_BUS_FMT_RGB888_1X24;
> +	}
>   
>   	clk_set_rate(lcdif->clk, m->crtc_clock * 1000);

[...]
Ying Liu May 10, 2023, 8:30 a.m. UTC | #2 
On Tue, May 9, 2023 at 10:14 AM Marek Vasut <marex@denx.de> wrote:
>
> On 5/8/23 07:57, Liu Ying wrote:
>
> Hi,

Hi,

>
> > diff --git a/drivers/gpu/drm/mxsfb/lcdif_kms.c b/drivers/gpu/drm/mxsfb/lcdif_kms.c
> > index 262bc43b1079..e54200a9fcb9 100644
> > --- a/drivers/gpu/drm/mxsfb/lcdif_kms.c
> > +++ b/drivers/gpu/drm/mxsfb/lcdif_kms.c
> > @@ -394,7 +394,7 @@ static void lcdif_crtc_mode_set_nofb(struct lcdif_drm_private *lcdif,
> >       struct drm_display_mode *m = &lcdif->crtc.state->adjusted_mode;
> >       u32 bus_flags = 0;
> >
> > -     if (lcdif->bridge && lcdif->bridge->timings)
> > +     if (lcdif->bridge->timings)
> >               bus_flags = lcdif->bridge->timings->input_bus_flags;
> >       else if (bridge_state)
> >               bus_flags = bridge_state->input_bus_cfg.flags;
> > @@ -463,30 +463,21 @@ static void lcdif_crtc_atomic_enable(struct drm_crtc *crtc,
> >       struct drm_display_mode *m = &lcdif->crtc.state->adjusted_mode;
> >       struct drm_bridge_state *bridge_state = NULL;
> >       struct drm_device *drm = lcdif->drm;
> > -     u32 bus_format = 0;
> > +     u32 bus_format;
> >       dma_addr_t paddr;
> >
> > -     /* If there is a bridge attached to the LCDIF, use its bus format */
> > -     if (lcdif->bridge) {
> > -             bridge_state =
> > -                     drm_atomic_get_new_bridge_state(state,
> > -                                                     lcdif->bridge);
> > -             if (!bridge_state)
> > -                     bus_format = MEDIA_BUS_FMT_FIXED;
> > -             else
> > -                     bus_format = bridge_state->input_bus_cfg.format;
> > -
> > -             if (bus_format == MEDIA_BUS_FMT_FIXED) {
> > -                     dev_warn_once(drm->dev,
> > -                                   "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
> > -                                   "Please fix bridge driver by handling atomic_get_input_bus_fmts.\n");
> > -                     bus_format = MEDIA_BUS_FMT_RGB888_1X24;
> > -             }
> > -     }
> > +     bridge_state = drm_atomic_get_new_bridge_state(state, lcdif->bridge);
> > +     if (!bridge_state)
> > +             bus_format = MEDIA_BUS_FMT_FIXED;
> > +     else
> > +             bus_format = bridge_state->input_bus_cfg.format;
>
> The code below seems to change the logic slightly.
>
> Could it happen that:
> - bridge_state is valid (i.e. non-NULL)
> - bridge_state->input_bus_cfg.format is set to 0 (i.e. not set) ?
>    (note that MEDIA_BUS_FMT_FIXED is defined as 0x0001)

Yes, bridge_state->input_bus_cfg.format could be zero.
Will keep the below default MEDIA_BUS_FMT_RGB888_1X24
bus format setting in next version.

Regards,
Liu Ying

>
> > -     /* If all else fails, default to RGB888_1X24 */
> > -     if (!bus_format)
> > +     if (bus_format == MEDIA_BUS_FMT_FIXED) {
> > +             dev_warn_once(drm->dev,
> > +                           "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
> > +                           "Please fix bridge driver by handling atomic_get_input_bus_fmts.\n");
> >               bus_format = MEDIA_BUS_FMT_RGB888_1X24;
> > +     }
> >
> >       clk_set_rate(lcdif->clk, m->crtc_clock * 1000);
>
> [...]
Marek Vasut May 10, 2023, 8:40 a.m. UTC | #3 
On 5/10/23 10:30, Ying Liu wrote:
> On Tue, May 9, 2023 at 10:14 AM Marek Vasut <marex@denx.de> wrote:
>>
>> On 5/8/23 07:57, Liu Ying wrote:
>>
>> Hi,
> 
> Hi,

Hi,

>>> diff --git a/drivers/gpu/drm/mxsfb/lcdif_kms.c b/drivers/gpu/drm/mxsfb/lcdif_kms.c
>>> index 262bc43b1079..e54200a9fcb9 100644
>>> --- a/drivers/gpu/drm/mxsfb/lcdif_kms.c
>>> +++ b/drivers/gpu/drm/mxsfb/lcdif_kms.c
>>> @@ -394,7 +394,7 @@ static void lcdif_crtc_mode_set_nofb(struct lcdif_drm_private *lcdif,
>>>        struct drm_display_mode *m = &lcdif->crtc.state->adjusted_mode;
>>>        u32 bus_flags = 0;
>>>
>>> -     if (lcdif->bridge && lcdif->bridge->timings)
>>> +     if (lcdif->bridge->timings)
>>>                bus_flags = lcdif->bridge->timings->input_bus_flags;
>>>        else if (bridge_state)
>>>                bus_flags = bridge_state->input_bus_cfg.flags;
>>> @@ -463,30 +463,21 @@ static void lcdif_crtc_atomic_enable(struct drm_crtc *crtc,
>>>        struct drm_display_mode *m = &lcdif->crtc.state->adjusted_mode;
>>>        struct drm_bridge_state *bridge_state = NULL;
>>>        struct drm_device *drm = lcdif->drm;
>>> -     u32 bus_format = 0;
>>> +     u32 bus_format;
>>>        dma_addr_t paddr;
>>>
>>> -     /* If there is a bridge attached to the LCDIF, use its bus format */
>>> -     if (lcdif->bridge) {
>>> -             bridge_state =
>>> -                     drm_atomic_get_new_bridge_state(state,
>>> -                                                     lcdif->bridge);
>>> -             if (!bridge_state)
>>> -                     bus_format = MEDIA_BUS_FMT_FIXED;
>>> -             else
>>> -                     bus_format = bridge_state->input_bus_cfg.format;
>>> -
>>> -             if (bus_format == MEDIA_BUS_FMT_FIXED) {
>>> -                     dev_warn_once(drm->dev,
>>> -                                   "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
>>> -                                   "Please fix bridge driver by handling atomic_get_input_bus_fmts.\n");
>>> -                     bus_format = MEDIA_BUS_FMT_RGB888_1X24;
>>> -             }
>>> -     }
>>> +     bridge_state = drm_atomic_get_new_bridge_state(state, lcdif->bridge);
>>> +     if (!bridge_state)
>>> +             bus_format = MEDIA_BUS_FMT_FIXED;
>>> +     else
>>> +             bus_format = bridge_state->input_bus_cfg.format;
>>
>> The code below seems to change the logic slightly.
>>
>> Could it happen that:
>> - bridge_state is valid (i.e. non-NULL)
>> - bridge_state->input_bus_cfg.format is set to 0 (i.e. not set) ?
>>     (note that MEDIA_BUS_FMT_FIXED is defined as 0x0001)
> 
> Yes, bridge_state->input_bus_cfg.format could be zero.
> Will keep the below default MEDIA_BUS_FMT_RGB888_1X24
> bus format setting in next version.

Thanks for confirming.

The rest of the series looks good, sorry for the delay in reviews.
diff mbox series

Patch

diff --git a/drivers/gpu/drm/mxsfb/lcdif_kms.c b/drivers/gpu/drm/mxsfb/lcdif_kms.c
index 262bc43b1079..e54200a9fcb9 100644
--- a/drivers/gpu/drm/mxsfb/lcdif_kms.c
+++ b/drivers/gpu/drm/mxsfb/lcdif_kms.c
@@ -394,7 +394,7 @@  static void lcdif_crtc_mode_set_nofb(struct lcdif_drm_private *lcdif,
 	struct drm_display_mode *m = &lcdif->crtc.state->adjusted_mode;
 	u32 bus_flags = 0;
 
-	if (lcdif->bridge && lcdif->bridge->timings)
+	if (lcdif->bridge->timings)
 		bus_flags = lcdif->bridge->timings->input_bus_flags;
 	else if (bridge_state)
 		bus_flags = bridge_state->input_bus_cfg.flags;
@@ -463,30 +463,21 @@  static void lcdif_crtc_atomic_enable(struct drm_crtc *crtc,
 	struct drm_display_mode *m = &lcdif->crtc.state->adjusted_mode;
 	struct drm_bridge_state *bridge_state = NULL;
 	struct drm_device *drm = lcdif->drm;
-	u32 bus_format = 0;
+	u32 bus_format;
 	dma_addr_t paddr;
 
-	/* If there is a bridge attached to the LCDIF, use its bus format */
-	if (lcdif->bridge) {
-		bridge_state =
-			drm_atomic_get_new_bridge_state(state,
-							lcdif->bridge);
-		if (!bridge_state)
-			bus_format = MEDIA_BUS_FMT_FIXED;
-		else
-			bus_format = bridge_state->input_bus_cfg.format;
-
-		if (bus_format == MEDIA_BUS_FMT_FIXED) {
-			dev_warn_once(drm->dev,
-				      "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
-				      "Please fix bridge driver by handling atomic_get_input_bus_fmts.\n");
-			bus_format = MEDIA_BUS_FMT_RGB888_1X24;
-		}
-	}
+	bridge_state = drm_atomic_get_new_bridge_state(state, lcdif->bridge);
+	if (!bridge_state)
+		bus_format = MEDIA_BUS_FMT_FIXED;
+	else
+		bus_format = bridge_state->input_bus_cfg.format;
 
-	/* If all else fails, default to RGB888_1X24 */
-	if (!bus_format)
+	if (bus_format == MEDIA_BUS_FMT_FIXED) {
+		dev_warn_once(drm->dev,
+			      "Bridge does not provide bus format, assuming MEDIA_BUS_FMT_RGB888_1X24.\n"
+			      "Please fix bridge driver by handling atomic_get_input_bus_fmts.\n");
 		bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+	}
 
 	clk_set_rate(lcdif->clk, m->crtc_clock * 1000);