Re: HEADSUP usb2/usb4bsd to become default in GENERIC

Hans Petter Selasky schrieb:
> On Monday 09 February 2009, Christoph Mallon wrote:
>> Hans Petter Selasky schrieb:
>>> On Monday 09 February 2009, Christoph Mallon wrote:
>>>> Christoph Mallon schrieb:
>>>>> are named "err" or "error". This should be investigated, so here's the
>>>>> complete list:
>>>> Sorry, my MUA seems to have damaged the list. You can get the list here:
>>>> http://tron.homeunix.org/usb2.unread.log
>>> I think some of these errors depend if you have USB debugging compiled or
>>> not. At least GCC does not warn?
>> No, it does not depend on USB debugging.
>> GCC has no warning at all for variables which are only assigned to.
>> It only can warn about variables, which are only initialised.
>>
>> {
>>    int x = 23; // GCC warns here ...
>>    int y;      // ... but not here - cparser does
>>    y = 42;
>>    y++;
>> }
>>
>> cparser has an analysis, which can warn about "y", too.
>>
>> I manually verified all 40 warnings and I cannot find any users (i.e.
>> readers) for these variables.
> 
> What is the correct way to discard the return argument of a function? That's 
> basically what most of the warnings are about.
> 
> 1) (void)my_fn() cast
> 2) if (my_fn()) { }
> 3) err = my_fn();
> 4) my_fn();

Just to understand this correctly: You want to discard error codes?


Basically I see four categories:

1) Getting the softc and not using it.
This can be removed completely.
Example:
   sc = ATMEGA_BUS2SC(xfer->xroot->bus);

2) calling mtx_owned() and discarding the return value.
Can be removed, too, after checking that the value is really unnecessary.
Example:
   use_polling = mtx_owned(xfer->xroot->xfer_mtx) ? 1 : 0;

3) Getting some value and not using it.
Can be removed, too, after checking that the value is really unnecessary.
Example:
   ep_no = (xfer->endpoint & UE_ADDR);

4) The rest are return values of functions, which contain error codes.
Discarding them is questionable at best.
Example: (err is not read)
     if (udev->flags.suspended) {
       err = DEVICE_SUSPEND(iface->subdev);
       device_printf(iface->subdev, "Suspend failed\n");
     }
     return (0);   /* success */