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[PATCH] omapfb: dss: Handle return error in dss_init_ports.

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  [PATCH] omapfb: dss: Handle return error in dss_init_ports. Arvind Yadav <arvind.yadav.cs@gmail.com> - 2017-02-03 13:30 +0100
    Re: [PATCH] omapfb: dss: Handle return error in dss_init_ports. Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> - 2017-02-06 16:30 +0100
      Re: [PATCH] omapfb: dss: Handle return error in dss_init_ports. Arvind Yadav <arvind.yadav.cs@gmail.com> - 2017-02-07 13:20 +0100
        Re: [PATCH] omapfb: dss: Handle return error in dss_init_ports. Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> - 2017-02-08 11:40 +0100
          Re: [PATCH] omapfb: dss: Handle return error in dss_init_ports. Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> - 2017-02-08 15:40 +0100
            Re: [PATCH] omapfb: dss: Handle return error in dss_init_ports. Arvind Yadav <arvind.yadav.cs@gmail.com> - 2017-02-09 11:10 +0100

#1573060 — [PATCH] omapfb: dss: Handle return error in dss_init_ports.

Here, dss_init_ports is not handling return error form
dpi_init_port and sdi_init_port. Now dss_init_ports is returning
always 0. And it's making below code as a dead code.

static int dss_bind(struct device *dev)
{
  .
  .
  r = dss_init_ports(pdev); //dss_init_ports will return always 0
  if (r)// This condition will always false
      goto err_init_ports; //Dead Code
  .
  .
}

This change is to handle return error from dpi_init_port and
sdi_init_port. Also, It will remove dead code from function 'dss_bind'.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
---
 drivers/video/fbdev/omap2/omapfb/dss/dss.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/video/fbdev/omap2/omapfb/dss/dss.c b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
index 47d7f69..15a0dab 100644
--- a/drivers/video/fbdev/omap2/omapfb/dss/dss.c
+++ b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
@@ -946,6 +946,7 @@ static int dss_init_ports(struct platform_device *pdev)
 	struct device_node *parent = pdev->dev.of_node;
 	struct device_node *port;
 	int r;
+	int ret = 0;
 
 	if (parent == NULL)
 		return 0;
@@ -972,17 +973,17 @@ static int dss_init_ports(struct platform_device *pdev)
 
 		switch (port_type) {
 		case OMAP_DISPLAY_TYPE_DPI:
-			dpi_init_port(pdev, port);
+			ret = dpi_init_port(pdev, port);
 			break;
 		case OMAP_DISPLAY_TYPE_SDI:
-			sdi_init_port(pdev, port);
+			ret = sdi_init_port(pdev, port);
 			break;
 		default:
 			break;
 		}
 	} while ((port = omapdss_of_get_next_port(parent, port)) != NULL);
 
-	return 0;
+	return ret;
 }
 
 static void dss_uninit_ports(struct platform_device *pdev)
-- 
1.9.1

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#1574902

Hi,

On Friday, February 03, 2017 05:53:45 PM Arvind Yadav wrote:
> Here, dss_init_ports is not handling return error form
> dpi_init_port and sdi_init_port. Now dss_init_ports is returning
> always 0. And it's making below code as a dead code.
> 
> static int dss_bind(struct device *dev)
> {
>   .
>   .
>   r = dss_init_ports(pdev); //dss_init_ports will return always 0
>   if (r)// This condition will always false
>       goto err_init_ports; //Dead Code
>   .
>   .
> }
> 
> This change is to handle return error from dpi_init_port and
> sdi_init_port. Also, It will remove dead code from function 'dss_bind'.
> 
> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
> ---
>  drivers/video/fbdev/omap2/omapfb/dss/dss.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/video/fbdev/omap2/omapfb/dss/dss.c b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> index 47d7f69..15a0dab 100644
> --- a/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> +++ b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> @@ -946,6 +946,7 @@ static int dss_init_ports(struct platform_device *pdev)
>  	struct device_node *parent = pdev->dev.of_node;
>  	struct device_node *port;
>  	int r;
> +	int ret = 0;
>  
>  	if (parent == NULL)
>  		return 0;
> @@ -972,17 +973,17 @@ static int dss_init_ports(struct platform_device *pdev)
>  
>  		switch (port_type) {
>  		case OMAP_DISPLAY_TYPE_DPI:
> -			dpi_init_port(pdev, port);
> +			ret = dpi_init_port(pdev, port);
>  			break;
>  		case OMAP_DISPLAY_TYPE_SDI:
> -			sdi_init_port(pdev, port);
> +			ret = sdi_init_port(pdev, port);
>  			break;
>  		default:
>  			break;
>  		}
>  	} while ((port = omapdss_of_get_next_port(parent, port)) != NULL);

Shouldn't initialization be stopped after the first failure?

i.e.:

	} while (!ret && (port = omapdss_of_get_next_port(parent, port)) != NULL);

Also the cleanup of the partial initialization is missing.
From looking at the code we should do something like this
before returning:

	if (ret)
		dss_uninit_ports(pdev);

(dpi_uninit_port() & sdi_uninit_port() skip not fully
initialized ports)

> -	return 0;
> +	return ret;
>  }
>  
>  static void dss_uninit_ports(struct platform_device *pdev)

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

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#1575609

Hi,

In dss_init_ports, There is no need to add dss_uninit_ports before 
returning.
Because it's already take care in dss_bind. dss_bind  is handling
dss_uninit_ports in error path.

-Arvind


On Monday 06 February 2017 08:58 PM, Bartlomiej Zolnierkiewicz wrote:
> dpi_uninit_port() & sdi_uninit_port() skip not fully
> initialized port

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#1576424

Hi,

On Tuesday, February 07, 2017 05:41:37 PM Arvind Yadav wrote:
> Hi,
> 
> In dss_init_ports, There is no need to add dss_uninit_ports before 
> returning.
> Because it's already take care in dss_bind. dss_bind  is handling
> dss_uninit_ports in error path.

It doesn't handle cleanup of partially initialized ports,
please look at the code:

...
	r = dss_init_ports(pdev);
	if (r)
		goto err_init_ports;
...
err_runtime_get:
	pm_runtime_disable(&pdev->dev);
	dss_uninit_ports(pdev);
err_init_ports:
	if (dss.video1_pll)
		dss_video_pll_uninit(dss.video1_pll);
...

dss_uninit_ports() is not called on partially initialized
ports (when dss_init_ports() returns an error we go straight
into err_init_ports label and skip dss_uninit_ports())

> -Arvind
> 
> 
> On Monday 06 February 2017 08:58 PM, Bartlomiej Zolnierkiewicz wrote:
> > dpi_uninit_port() & sdi_uninit_port() skip not fully
> > initialized port

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

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#1576624

On Wednesday, February 08, 2017 11:25:47 AM Bartlomiej Zolnierkiewicz wrote:
> 
> Hi,
> 
> On Tuesday, February 07, 2017 05:41:37 PM Arvind Yadav wrote:
> > Hi,
> > 
> > In dss_init_ports, There is no need to add dss_uninit_ports before 
> > returning.
> > Because it's already take care in dss_bind. dss_bind  is handling
> > dss_uninit_ports in error path.
> 
> It doesn't handle cleanup of partially initialized ports,

BTW by "partially initialized ports" here I mean cases like
i.e. dpi port fully initialized and sdi one not initialized

> please look at the code:
> 
> ...
> 	r = dss_init_ports(pdev);
> 	if (r)
> 		goto err_init_ports;
> ...
> err_runtime_get:
> 	pm_runtime_disable(&pdev->dev);
> 	dss_uninit_ports(pdev);
> err_init_ports:
> 	if (dss.video1_pll)
> 		dss_video_pll_uninit(dss.video1_pll);
> ...
> 
> dss_uninit_ports() is not called on partially initialized

ditto

> ports (when dss_init_ports() returns an error we go straight
> into err_init_ports label and skip dss_uninit_ports())
> 
> > -Arvind
> > 
> > 
> > On Monday 06 February 2017 08:58 PM, Bartlomiej Zolnierkiewicz wrote:
> > > dpi_uninit_port() & sdi_uninit_port() skip not fully
> > > initialized port

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

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#1577445

Hi,
Yes, We will have to handle cleanup of partially initialized ports.
As per your suggestion, I have done the changes.

Thanks
-Arvind

On Wednesday 08 February 2017 07:51 PM, Bartlomiej Zolnierkiewicz wrote:
> On Wednesday, February 08, 2017 11:25:47 AM Bartlomiej Zolnierkiewicz wrote:
>> Hi,
>>
>> On Tuesday, February 07, 2017 05:41:37 PM Arvind Yadav wrote:
>>> Hi,
>>>
>>> In dss_init_ports, There is no need to add dss_uninit_ports before
>>> returning.
>>> Because it's already take care in dss_bind. dss_bind  is handling
>>> dss_uninit_ports in error path.
>> It doesn't handle cleanup of partially initialized ports,
> BTW by "partially initialized ports" here I mean cases like
> i.e. dpi port fully initialized and sdi one not initialized
>
>> please look at the code:
>>
>> ...
>> 	r = dss_init_ports(pdev);
>> 	if (r)
>> 		goto err_init_ports;
>> ...
>> err_runtime_get:
>> 	pm_runtime_disable(&pdev->dev);
>> 	dss_uninit_ports(pdev);
>> err_init_ports:
>> 	if (dss.video1_pll)
>> 		dss_video_pll_uninit(dss.video1_pll);
>> ...
>>
>> dss_uninit_ports() is not called on partially initialized
> ditto
>
>> ports (when dss_init_ports() returns an error we go straight
>> into err_init_ports label and skip dss_uninit_ports())
>>
>>> -Arvind
>>>
>>>
>>> On Monday 06 February 2017 08:58 PM, Bartlomiej Zolnierkiewicz wrote:
>>>> dpi_uninit_port() & sdi_uninit_port() skip not fully
>>>> initialized port
> Best regards,
> --
> Bartlomiej Zolnierkiewicz
> Samsung R&D Institute Poland
> Samsung Electronics
>

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