linux-kernel - Re: [PATCH 1/4] input: tablet: pegasus_notetaker: Track usb control msg errors

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Date:	Thu, 21 Jul 2016 13:06:57 +0200
From:	Martin Kepplinger <martink@...teo.de>
To:	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:	linux-kernel@...r.kernel.org, linux-input@...r.kernel.org
Subject: Re: [PATCH 1/4] input: tablet: pegasus_notetaker: Track usb control
 msg errors

Am 2016-07-20 um 23:06 schrieb Dmitry Torokhov:
> Hi Martin,
> 
> On Mon, Jul 18, 2016 at 04:29:06PM +0200, Martin Kepplinger wrote:
>> Signed-off-by: Martin Kepplinger <martink@...teo.de>
>> ---
>>  drivers/input/tablet/pegasus_notetaker.c | 26 ++++++++++++++++++--------
>>  1 file changed, 18 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/input/tablet/pegasus_notetaker.c b/drivers/input/tablet/pegasus_notetaker.c
>> index 83aa583..27cb352 100644
>> --- a/drivers/input/tablet/pegasus_notetaker.c
>> +++ b/drivers/input/tablet/pegasus_notetaker.c
>> @@ -79,7 +79,7 @@ struct pegasus {
>>  	struct work_struct init;
>>  };
>>  
>> -static void pegasus_control_msg(struct pegasus *pegasus, u8 *data, int len)
>> +static int pegasus_control_msg(struct pegasus *pegasus, u8 *data, int len)
>>  {
>>  	const int sizeof_buf = len + 2;
>>  	int result;
>> @@ -87,7 +87,7 @@ static void pegasus_control_msg(struct pegasus *pegasus, u8 *data, int len)
>>  
>>  	cmd_buf = kmalloc(sizeof_buf, GFP_KERNEL);
>>  	if (!cmd_buf)
>> -		return;
>> +		return -ENOMEM;
>>  
>>  	cmd_buf[0] = NOTETAKER_REPORT_ID;
>>  	cmd_buf[1] = len;
>> @@ -100,17 +100,23 @@ static void pegasus_control_msg(struct pegasus *pegasus, u8 *data, int len)
>>  				 0, 0, cmd_buf, sizeof_buf,
>>  				 USB_CTRL_SET_TIMEOUT);
>>  
>> -	if (result != sizeof_buf)
>> -		dev_err(&pegasus->usbdev->dev, "control msg error\n");
>> +	if (result != sizeof_buf) {
>> +		if (result >= 0)
>> +			result = -EIO;
>> +		dev_err(&pegasus->usbdev->dev, "control msg error: %d\n",
>> +			result);
>> +	}
>>  
>>  	kfree(cmd_buf);
>> +
>> +	return result;
> 
> Your 4th patch relies on pegasus_control_msg() returning 0 on success,
> otherwise you will not restart the URB when doing reset resume. I
> rearranged the code here so we free cmd_buf right after calling
> usb_control_msg() and the explicitly returnig 0 in success branch.
> 

Yes, I saw it. Thanks for your explaining and fixing!

>>  }
>>  
>> -static void pegasus_set_mode(struct pegasus *pegasus, u8 mode, u8 led)
>> +static int pegasus_set_mode(struct pegasus *pegasus, u8 mode, u8 led)
>>  {
>>  	u8 cmd[] = {NOTETAKER_SET_CMD, NOTETAKER_SET_MODE, led, mode};
>>  
>> -	pegasus_control_msg(pegasus, cmd, sizeof(cmd));
>> +	return pegasus_control_msg(pegasus, cmd, sizeof(cmd));
>>  }
>>  
>>  static void pegasus_parse_packet(struct pegasus *pegasus)
>> @@ -184,8 +190,12 @@ static void pegasus_irq(struct urb *urb)
>>  static void pegasus_init(struct work_struct *work)
>>  {
>>  	struct pegasus *pegasus = container_of(work, struct pegasus, init);
>> +	int retval;
>>  
>> -	pegasus_set_mode(pegasus, PEN_MODE_XY, NOTETAKER_LED_MOUSE);
>> +	retval = pegasus_set_mode(pegasus, PEN_MODE_XY, NOTETAKER_LED_MOUSE);
>> +	if (retval < 0)
>> +		dev_err(&pegasus->usbdev->dev, "pegasus_set_mode error: %d\n",
>> +			retval);
>>  }
>>  
>>  static int pegasus_open(struct input_dev *dev)
>> @@ -201,7 +211,7 @@ static int pegasus_open(struct input_dev *dev)
>>  	if (usb_submit_urb(pegasus->irq, GFP_KERNEL))
>>  		retval = -EIO;
>>  
>> -	pegasus_set_mode(pegasus, PEN_MODE_XY, NOTETAKER_LED_MOUSE);
>> +	retval = pegasus_set_mode(pegasus, PEN_MODE_XY, NOTETAKER_LED_MOUSE);
>>  
>>  	usb_autopm_put_interface(pegasus->intf);
>>  
> 
> Thanks.
>