[PATCH] usb: gadget: f_acm: don't disable disabled EP

[PATCH] usb: gadget: f_acm: don't disable disabled EP

[Michał Mirosław]

Make debugging real problems easier by not trying to disable an EP that
was not yet enabled.

Fixes: 4aab757ca44a ("usb: gadget: f_acm: eliminate abuse of ep->driver data")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
---
 drivers/usb/gadget/function/f_acm.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/gadget/function/f_acm.c b/drivers/usb/gadget/function/f_acm.c
index 200596ea9557..46647bfac2ef 100644
--- a/drivers/usb/gadget/function/f_acm.c
+++ b/drivers/usb/gadget/function/f_acm.c
@@ -425,9 +425,11 @@ static int acm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 	/* we know alt == 0, so this is an activation or a reset */
 
 	if (intf == acm->ctrl_id) {
-		dev_vdbg(&cdev->gadget->dev,
-				"reset acm control interface %d\n", intf);
-		usb_ep_disable(acm->notify);
+		if (acm->notify->enabled) {
+			dev_vdbg(&cdev->gadget->dev,
+					"reset acm control interface %d\n", intf);
+			usb_ep_disable(acm->notify);
+		}
 
 		if (!acm->notify->desc)
 			if (config_ep_by_speed(cdev->gadget, f, acm->notify))
-- 
2.20.1

Re: [PATCH] usb: gadget: f_acm: don't disable disabled EP

[Peter Chen]

On 20-05-28 20:30:28, Michał Mirosław wrote:
> Make debugging real problems easier by not trying to disable an EP that
> was not yet enabled.
> 
> Fixes: 4aab757ca44a ("usb: gadget: f_acm: eliminate abuse of ep->driver data")
> Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
> ---
>  drivers/usb/gadget/function/f_acm.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/usb/gadget/function/f_acm.c b/drivers/usb/gadget/function/f_acm.c
> index 200596ea9557..46647bfac2ef 100644
> --- a/drivers/usb/gadget/function/f_acm.c
> +++ b/drivers/usb/gadget/function/f_acm.c
> @@ -425,9 +425,11 @@ static int acm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
>  	/* we know alt == 0, so this is an activation or a reset */
>  
>  	if (intf == acm->ctrl_id) {
> -		dev_vdbg(&cdev->gadget->dev,
> -				"reset acm control interface %d\n", intf);
> -		usb_ep_disable(acm->notify);
> +		if (acm->notify->enabled) {
> +			dev_vdbg(&cdev->gadget->dev,
> +					"reset acm control interface %d\n", intf);
> +			usb_ep_disable(acm->notify);
> +		}

But it does not fix any issues, the usb_ep_disable checks 'enabled' flag.

-- 

Thanks,
Peter Chen

Re: [PATCH] usb: gadget: f_acm: don't disable disabled EP

[Michał Mirosław]

On Fri, May 29, 2020 at 08:10:40AM +0000, Peter Chen wrote:
> On 20-05-28 20:30:28, Michał Mirosław wrote:
> > Make debugging real problems easier by not trying to disable an EP that
> > was not yet enabled.
> > 
> > Fixes: 4aab757ca44a ("usb: gadget: f_acm: eliminate abuse of ep->driver data")
> > Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
> > ---
> >  drivers/usb/gadget/function/f_acm.c | 8 +++++---
> >  1 file changed, 5 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/usb/gadget/function/f_acm.c b/drivers/usb/gadget/function/f_acm.c
> > index 200596ea9557..46647bfac2ef 100644
> > --- a/drivers/usb/gadget/function/f_acm.c
> > +++ b/drivers/usb/gadget/function/f_acm.c
> > @@ -425,9 +425,11 @@ static int acm_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
> >  	/* we know alt == 0, so this is an activation or a reset */
> >  
> >  	if (intf == acm->ctrl_id) {
> > -		dev_vdbg(&cdev->gadget->dev,
> > -				"reset acm control interface %d\n", intf);
> > -		usb_ep_disable(acm->notify);
> > +		if (acm->notify->enabled) {
> > +			dev_vdbg(&cdev->gadget->dev,
> > +					"reset acm control interface %d\n", intf);
> > +			usb_ep_disable(acm->notify);
> > +		}
> 
> But it does not fix any issues, the usb_ep_disable checks 'enabled' flag.

It generates spurious trace events if you enable them.

Best Regards,
Michał Mirosław

RE: [PATCH] usb: gadget: f_acm: don't disable disabled EP

[Peter Chen]

 
> > > @@ -425,9 +425,11 @@ static int acm_set_alt(struct usb_function *f, unsigned
> intf, unsigned alt)
> > >  	/* we know alt == 0, so this is an activation or a reset */
> > >
> > >  	if (intf == acm->ctrl_id) {
> > > -		dev_vdbg(&cdev->gadget->dev,
> > > -				"reset acm control interface %d\n", intf);
> > > -		usb_ep_disable(acm->notify);
> > > +		if (acm->notify->enabled) {
> > > +			dev_vdbg(&cdev->gadget->dev,
> > > +					"reset acm control interface %d\n", intf);
> > > +			usb_ep_disable(acm->notify);
> > > +		}
> >
> > But it does not fix any issues, the usb_ep_disable checks 'enabled' flag.
> 
> It generates spurious trace events if you enable them.
> 

You mean the trace events from core.c? If it is, we could try to improve it
and indicate it is already enabled or disabled.

Peter

Re: [PATCH] usb: gadget: f_acm: don't disable disabled EP

[Michał Mirosław]

On Sat, May 30, 2020 at 01:03:17AM +0000, Peter Chen wrote:
>  
> > > > @@ -425,9 +425,11 @@ static int acm_set_alt(struct usb_function *f, unsigned
> > intf, unsigned alt)
> > > >  	/* we know alt == 0, so this is an activation or a reset */
> > > >
> > > >  	if (intf == acm->ctrl_id) {
> > > > -		dev_vdbg(&cdev->gadget->dev,
> > > > -				"reset acm control interface %d\n", intf);
> > > > -		usb_ep_disable(acm->notify);
> > > > +		if (acm->notify->enabled) {
> > > > +			dev_vdbg(&cdev->gadget->dev,
> > > > +					"reset acm control interface %d\n", intf);
> > > > +			usb_ep_disable(acm->notify);
> > > > +		}
> > >
> > > But it does not fix any issues, the usb_ep_disable checks 'enabled' flag.
> > 
> > It generates spurious trace events if you enable them.
> You mean the trace events from core.c? If it is, we could try to improve it
> and indicate it is already enabled or disabled.

It is indicated in return code, but the problem is that this generates
noise and wastes debugging time. The problem I was seeing manifested
itself as disabling disabled EPs and desync of EP state between core
and UDC driver. The patch avoids the noise and makes the code obvious.
(This check was there at some point in time, BTW.)

Best Regards,
Michał Mirosław

Re: [PATCH] usb: gadget: f_acm: don't disable disabled EP

[Peter Chen]

On 20-05-30 19:15:52, Michał Mirosław wrote:
> On Sat, May 30, 2020 at 01:03:17AM +0000, Peter Chen wrote:
> >  
> > > > > @@ -425,9 +425,11 @@ static int acm_set_alt(struct usb_function *f, unsigned
> > > intf, unsigned alt)
> > > > >  	/* we know alt == 0, so this is an activation or a reset */
> > > > >
> > > > >  	if (intf == acm->ctrl_id) {
> > > > > -		dev_vdbg(&cdev->gadget->dev,
> > > > > -				"reset acm control interface %d\n", intf);
> > > > > -		usb_ep_disable(acm->notify);
> > > > > +		if (acm->notify->enabled) {
> > > > > +			dev_vdbg(&cdev->gadget->dev,
> > > > > +					"reset acm control interface %d\n", intf);
> > > > > +			usb_ep_disable(acm->notify);
> > > > > +		}
> > > >
> > > > But it does not fix any issues, the usb_ep_disable checks 'enabled' flag.
> > > 
> > > It generates spurious trace events if you enable them.
> > You mean the trace events from core.c? If it is, we could try to improve it
> > and indicate it is already enabled or disabled.
> 
> It is indicated in return code, but the problem is that this generates
> noise and wastes debugging time. The problem I was seeing manifested
> itself as disabling disabled EPs and desync of EP state between core
> and UDC driver. The patch avoids the noise and makes the code obvious.
> (This check was there at some point in time, BTW.)
> 

Reviewed-by: Peter Chen <peter.chen@nxp.com>



-- 

Thanks,
Peter Chen

RE: [PATCH] usb: gadget: f_acm: don't disable disabled EP

[Felipe Balbi]

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Peter Chen <peter.chen@nxp.com> writes:

>  
>> > > @@ -425,9 +425,11 @@ static int acm_set_alt(struct usb_function *f, unsigned
>> intf, unsigned alt)
>> > >  	/* we know alt == 0, so this is an activation or a reset */
>> > >
>> > >  	if (intf == acm->ctrl_id) {
>> > > -		dev_vdbg(&cdev->gadget->dev,
>> > > -				"reset acm control interface %d\n", intf);
>> > > -		usb_ep_disable(acm->notify);
>> > > +		if (acm->notify->enabled) {
>> > > +			dev_vdbg(&cdev->gadget->dev,
>> > > +					"reset acm control interface %d\n", intf);
>> > > +			usb_ep_disable(acm->notify);
>> > > +		}
>> >
>> > But it does not fix any issues, the usb_ep_disable checks 'enabled' flag.
>> 
>> It generates spurious trace events if you enable them.
>> 
>
> You mean the trace events from core.c? If it is, we could try to improve it
> and indicate it is already enabled or disabled.

I agree :-)

-- 
balbi

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Re: [PATCH] usb: gadget: f_acm: don't disable disabled EP

[Felipe Balbi]

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Michał Mirosław <mirq-linux@rere.qmqm.pl> writes:

> On Sat, May 30, 2020 at 01:03:17AM +0000, Peter Chen wrote:
>>  
>> > > > @@ -425,9 +425,11 @@ static int acm_set_alt(struct usb_function *f, unsigned
>> > intf, unsigned alt)
>> > > >  	/* we know alt == 0, so this is an activation or a reset */
>> > > >
>> > > >  	if (intf == acm->ctrl_id) {
>> > > > -		dev_vdbg(&cdev->gadget->dev,
>> > > > -				"reset acm control interface %d\n", intf);
>> > > > -		usb_ep_disable(acm->notify);
>> > > > +		if (acm->notify->enabled) {
>> > > > +			dev_vdbg(&cdev->gadget->dev,
>> > > > +					"reset acm control interface %d\n", intf);
>> > > > +			usb_ep_disable(acm->notify);
>> > > > +		}
>> > >
>> > > But it does not fix any issues, the usb_ep_disable checks 'enabled' flag.
>> > 
>> > It generates spurious trace events if you enable them.
>> You mean the trace events from core.c? If it is, we could try to improve it
>> and indicate it is already enabled or disabled.
>
> It is indicated in return code, but the problem is that this generates
> noise and wastes debugging time. The problem I was seeing manifested
> itself as disabling disabled EPs and desync of EP state between core
> and UDC driver. The patch avoids the noise and makes the code obvious.
> (This check was there at some point in time, BTW.)

I agree with this as well. But still, $subject doesn't look like a
candidate for the -rc :-) I'll apply it for the next merge window.

-- 
balbi

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