Le 24/08/2021 à 04:01, Fabio M. De Francesco a écrit :

On Tuesday, August 24, 2021 3:38:03 AM CEST Fabio M. De Francesco wrote:

quoted

I think that I've inadvertently switched the order by which usb_control_msg_send()
and memcpy() are called. I'm very sorry for not doing my tests, but (as I had said
before) at the moment I don't have my device with me.

No, I did not switch them. There must be something else...
Sorry for the noise.

Fabio

Hi,

'usb_control_msg_recv()' looks like:

int usb_control_msg_recv(struct usb_device *dev, __u8 endpoint, ...)
{
	unsigned int pipe = usb_rcvctrlpipe(dev, endpoint);
	...
	ret = usb_control_msg(dev, pipe, ...);


'usb_control_msg()' looks like:
int usb_control_msg(struct usb_device *dev, unsigned int pipe, ...)
{


The difference is that one expect an 'endpoint' (and compute the pipe 
from it), and the other expect a 'pipe'.

Also, in your code, 'pipe' looks un-initialized.


So, my guess is that you should rename 'pipe' into 'endpoint' (to keep 
the semantic), have "endpoint = 0;" somewhere and pass it to 
usb_control_msg_{recv|send}.
Or just remove 'pipe' and pass an explicit 0 directly.

Not sure it is enough, but it looks like a difference between before and 
after your patch.


just my 2c,
CJ