[PATCH] usb: gadget: fsl: Fix a wrong judgment in fsl_udc_probe()

[PATCH] usb: gadget: fsl: Fix a wrong judgment in fsl_udc_probe()

[Tang Bin]

If the function "platform_get_irq()" failed, the negative value
returned will not be detected here, including "-EPROBE_DEFER", which
causes the application to fail to get the correct error message.
Thus it must be fixed.

Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
Signed-off-by: Shengju Zhang <zhangshengju@cmss.chinamobile.com>
---
 drivers/usb/gadget/udc/fsl_udc_core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/udc/fsl_udc_core.c b/drivers/usb/gadget/udc/fsl_udc_core.c
index ec6eda426..60853ad10 100644
--- a/drivers/usb/gadget/udc/fsl_udc_core.c
+++ b/drivers/usb/gadget/udc/fsl_udc_core.c
@@ -2441,8 +2441,8 @@ static int fsl_udc_probe(struct platform_device *pdev)
 	udc_controller->max_ep = (dccparams & DCCPARAMS_DEN_MASK) * 2;
 
 	udc_controller->irq = platform_get_irq(pdev, 0);
-	if (!udc_controller->irq) {
-		ret = -ENODEV;
+	if (udc_controller->irq <= 0) {
+		ret = udc_controller->irq ? : -ENODEV;
 		goto err_iounmap;
 	}
 
-- 
2.20.1.windows.1

Re: [PATCH] usb: gadget: fsl: Fix a wrong judgment in fsl_udc_probe()

[Markus Elfring]

> If the function "platform_get_irq()" failed, the negative value
> returned will not be detected here, including "-EPROBE_DEFER",

I suggest to adjust this change description.

Wording alternative:
  The negative return value (which could eventually be “-EPROBE_DEFER”)
  will not be detected here from a failed call of the function “platform_get_irq”.


> which causes the application to fail to get the correct error message.

Will another fine-tuning become relevant also for this wording?


> Thus it must be fixed.

Wording alternative:
  Thus adjust the error detection and corresponding exception handling.


> Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
> Signed-off-by: Shengju Zhang <zhangshengju@cmss.chinamobile.com>

How do you think about to add the tags “Fixes”, “Link” and “Reported-by”?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=c0cc271173b2e1c2d8d0ceaef14e4dfa79eefc0d#n584

usb: gadget: fsl_udc_core: Checking for a failed platform_get_irq() call in fsl_udc_probe()
https://lore.kernel.org/linux-usb/36341bb1-1e00-5eb1-d032-60dcc614ddaf@web.de/
https://lkml.org/lkml/2020/4/8/442

…
> +++ b/drivers/usb/gadget/udc/fsl_udc_core.c
> @@ -2441,8 +2441,8 @@ static int fsl_udc_probe(struct platform_device *pdev)
>  	udc_controller->max_ep = (dccparams & DCCPARAMS_DEN_MASK) * 2;
>
>  	udc_controller->irq = platform_get_irq(pdev, 0);
> -	if (!udc_controller->irq) {
> -		ret = -ENODEV;
> +	if (udc_controller->irq <= 0) {

Will such a failure predicate need any more clarification?

How does this check fit to the current software documentation?


> +		ret = udc_controller->irq ? : -ENODEV;

Will it be clearer to specify values for all cases in such a conditional operator
(instead of leaving one case empty)?

Regards,
Markus

Re: [PATCH] usb: gadget: fsl: Fix a wrong judgment in fsl_udc_probe()

[Tang Bin]

Hi Markus

On 2020/4/10 15:33, Markus Elfring wrote:
>> If the function "platform_get_irq()" failed, the negative value
>> returned will not be detected here, including "-EPROBE_DEFER",
> I suggest to adjust this change description.
>
> Wording alternative:
>    The negative return value (which could eventually be “-EPROBE_DEFER”)
>    will not be detected here from a failed call of the function “platform_get_irq”.
Hardware experiments show that the negative return value is not just 
"-EPROBE_DEFER".
>
>> which causes the application to fail to get the correct error message.
> Will another fine-tuning become relevant also for this wording?
Maybe that's not quite accurate.
>
>
>> Thus it must be fixed.
> Wording alternative:
>    Thus adjust the error detection and corresponding exception handling.
Got it.
>
>
>> Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
>> Signed-off-by: Shengju Zhang <zhangshengju@cmss.chinamobile.com>
> How do you think about to add the tags “Fixes”, “Link” and “Reported-by”?
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?id=c0cc271173b2e1c2d8d0ceaef14e4dfa79eefc0d#n584
>
> usb: gadget: fsl_udc_core: Checking for a failed platform_get_irq() call in fsl_udc_probe()
> https://lore.kernel.org/linux-usb/36341bb1-1e00-5eb1-d032-60dcc614ddaf@web.de/
> https://lkml.org/lkml/2020/4/8/442
>
> …
>> +++ b/drivers/usb/gadget/udc/fsl_udc_core.c
>> @@ -2441,8 +2441,8 @@ static int fsl_udc_probe(struct platform_device *pdev)
>>   	udc_controller->max_ep = (dccparams & DCCPARAMS_DEN_MASK) * 2;
>>
>>   	udc_controller->irq = platform_get_irq(pdev, 0);
>> -	if (!udc_controller->irq) {
>> -		ret = -ENODEV;
>> +	if (udc_controller->irq <= 0) {
> Will such a failure predicate need any more clarification?
>
> How does this check fit to the current software documentation?
Maybe my tags are not suitable.
>
>
>> +		ret = udc_controller->irq ? : -ENODEV;
> Will it be clearer to specify values for all cases in such a conditional operator
> (instead of leaving one case empty)?

I don't know what you mean of "instead of leaving one case empty". But 
by experiment, "ret = udc_controller->irq ? : -ENODEV" or "ret = 
udc_controller->irq < 0 ? udc_controller->irq : -ENODEV" should be 
suitable here.


Thank you for your guidance.

Tang Bin

Re: usb: gadget: fsl: Fix a wrong judgment in fsl_udc_probe()

[Markus Elfring]

> Hardware experiments show that the negative return value is not just "-EPROBE_DEFER".

How much will this specific error code influence our understanding
of the discussed software situation?


>>> +        ret = udc_controller->irq ? : -ENODEV;
>> Will it be clearer to specify values for all cases in such a conditional operator
>> (instead of leaving one case empty)?
>
> I don't know what you mean of "instead of leaving one case empty".

I suggest to reconsider also the proposed specification “… ? : …”.

Regards,
Markus

Re: usb: gadget: fsl: Fix a wrong judgment in fsl_udc_probe()

[Tang Bin]

Hi Markus:

On 2020/4/10 16:30, Markus Elfring wrote:
>> Hardware experiments show that the negative return value is not just "-EPROBE_DEFER".
> How much will this specific error code influence our understanding
> of the discussed software situation?
>
 From my superficial knowledge, I think we should not  think about it 
too complicated. The return value is just zero or negative, and for 
these negative return value, such as 
"-ENODEV"、"-ENXIO"、"-ENOENT"、“EPROBE_DEFER”，may be the same 
effect。But“-EPROBE_DEFER”has another  importment function: Driver 
requested deferred probing，which is used in cases where the dependency 
resource is not ready during the driver initialization process.
>>>> +        ret = udc_controller->irq ? : -ENODEV;
>>> Will it be clearer to specify values for all cases in such a conditional operator
>>> (instead of leaving one case empty)?
>> I don't know what you mean of "instead of leaving one case empty".
> I suggest to reconsider also the proposed specification “… ? : …”.

What you mean is the way I'm written？

I have provided two ways of patching, both functional can be verified on 
hardware.

Thanks for your patience.

Tang Bin

Re: [PATCH] usb: gadget: fsl: Fix a wrong judgment in fsl_udc_probe()

[Dan Carpenter]

On Fri, Apr 10, 2020 at 04:05:06PM +0800, Tang Bin wrote:
> > 
> > 
> > > Thus it must be fixed.
> > Wording alternative:
> >    Thus adjust the error detection and corresponding exception handling.
>
> Got it.

Wow...

No, don't listen to Markus when it comes to writing commit messages.
You couldn't find worse advice anywhere.  :P

regards,
dan carpenter

Re: [PATCH] usb: gadget: fsl: Fix a wrong judgment in fsl_udc_probe()

[Tang Bin]

Hi

On 2020/4/14 16:30, Dan Carpenter wrote:
> On Fri, Apr 10, 2020 at 04:05:06PM +0800, Tang Bin wrote:
>>>
>>>> Thus it must be fixed.
>>> Wording alternative:
>>>     Thus adjust the error detection and corresponding exception handling.
>> Got it.
> Wow...
>
> No, don't listen to Markus when it comes to writing commit messages.
> You couldn't find worse advice anywhere.  :P

I'm actively waiting for a reply from the maintainer. Thank you very much.

Tang Bin

Re: [PATCH] usb: gadget: fsl: Fix a wrong judgment in fsl_udc_probe()

[Li Yang]

On Tue, Apr 14, 2020 at 4:13 AM Tang Bin <tangbin@cmss.chinamobile.com> wrote:
>
> Hi
>
> On 2020/4/14 16:30, Dan Carpenter wrote:
> > On Fri, Apr 10, 2020 at 04:05:06PM +0800, Tang Bin wrote:
> >>>
> >>>> Thus it must be fixed.
> >>> Wording alternative:
> >>>     Thus adjust the error detection and corresponding exception handling.
> >> Got it.
> > Wow...
> >
> > No, don't listen to Markus when it comes to writing commit messages.
> > You couldn't find worse advice anywhere.  :P
>
> I'm actively waiting for a reply from the maintainer. Thank you very much.

Sorry for the late response.

Acked-by: Li Yang <leoyang.li@nxp.com>

Regards,
Leo

Re: [PATCH] usb: gadget: fsl: Fix a wrong judgment in fsl_udc_probe()

[Sergei Shtylyov]

Hello!

On 10.04.2020 4:58, Tang Bin wrote:

> If the function "platform_get_irq()" failed, the negative value
> returned will not be detected here, including "-EPROBE_DEFER", which
> causes the application to fail to get the correct error message.
> Thus it must be fixed.
> 
> Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
> Signed-off-by: Shengju Zhang <zhangshengju@cmss.chinamobile.com>
> ---
>   drivers/usb/gadget/udc/fsl_udc_core.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/gadget/udc/fsl_udc_core.c b/drivers/usb/gadget/udc/fsl_udc_core.c
> index ec6eda426..60853ad10 100644
> --- a/drivers/usb/gadget/udc/fsl_udc_core.c
> +++ b/drivers/usb/gadget/udc/fsl_udc_core.c
> @@ -2441,8 +2441,8 @@ static int fsl_udc_probe(struct platform_device *pdev)
>   	udc_controller->max_ep = (dccparams & DCCPARAMS_DEN_MASK) * 2;
>   
>   	udc_controller->irq = platform_get_irq(pdev, 0);
> -	if (!udc_controller->irq) {

    This check has always been wrong, doesn't account for real errors and
probe deferral...

> -		ret = -ENODEV;
> +	if (udc_controller->irq <= 0) {

    Note that platfrom_get_irq() no longer returns 0 on error.

> +		ret = udc_controller->irq ? : -ENODEV;
>   		goto err_iounmap;
>   	}

MBR, Sergei

Re: [PATCH] usb: gadget: fsl: Fix a wrong judgment in fsl_udc_probe()

[Sergei Shtylyov]

On 10.04.2020 4:58, Tang Bin wrote:

> If the function "platform_get_irq()" failed, the negative value
> returned will not be detected here, including "-EPROBE_DEFER", which
> causes the application to fail to get the correct error message.
> Thus it must be fixed.

    platform_get_irq() prints an appropriate error message, the problem is that
the current code calls request_irq() with error code instead of IRQ.

> Signed-off-by: Tang Bin <tangbin@cmss.chinamobile.com>
> Signed-off-by: Shengju Zhang <zhangshengju@cmss.chinamobile.com>
[...]

MBR, Sergei