usb audio callback questions.

usb audio callback questions.

[James Courtier-Dutton]

I have a question regarding the callbacks in the usbaudio.c driver.
The callback is defined as: -

/*
  * complete callback from data urb
  */
static void snd_complete_urb(struct urb *urb, struct pt_regs *regs)


The callback is set up with: -
u->urb->complete = snd_usb_complete_callback(snd_complete_urb);

The issue I have is that urb->complete is of type: -
struct urb;
typedef void (*usb_complete_t)(struct urb *);

struct urb
{
<snip>
         usb_complete_t complete;        // pointer to completion routine
<snip>
};

So, why is the "struct pt_regs *regs" there ?
I would think that
static void snd_complete_urb(struct urb *urb, struct pt_regs *regs)
should change to
static void snd_complete_urb(struct urb *urb)

Cheers
James



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Re: usb audio callback questions.

[Takashi Iwai]

At Sun, 06 Jul 2003 14:21:52 +0100,
James Courtier-Dutton wrote:
> 
> I have a question regarding the callbacks in the usbaudio.c driver.
> The callback is defined as: -
> 
> /*
>   * complete callback from data urb
>   */
> static void snd_complete_urb(struct urb *urb, struct pt_regs *regs)
> 
> 
> The callback is set up with: -
> u->urb->complete = snd_usb_complete_callback(snd_complete_urb);
> 
> The issue I have is that urb->complete is of type: -
> struct urb;
> typedef void (*usb_complete_t)(struct urb *);
> 
> struct urb
> {
> <snip>
>          usb_complete_t complete;        // pointer to completion routine
> <snip>
> };
> 
> So, why is the "struct pt_regs *regs" there ?
> I would think that
> static void snd_complete_urb(struct urb *urb, struct pt_regs *regs)
> should change to
> static void snd_complete_urb(struct urb *urb)

the second argument is added in the 2.5 USB-driver stack.
we have a (rather complex) wrapper for that, to compile the same
source both for 2.4 and 2.5 (even 2.2) kernels.
yeah, it needs more clean up...


Takashi


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