On Sun, 2012-09-09 at 23:01 +0200, walter harms wrote:
> Hi all,
> I am not sure if that is a good idea.
> it should be in the hands of the driver who to use these 'val'
>
> some driver may need a higher value like this one:
I doubt that any driver can actually work with the full range of
positive values, but at least they're less likely to crash.
> static int iguanair_set_tx_carrier(struct rc_dev *dev, uint32_t carrier)
> {
> struct iguanair *ir = dev->priv;
>
> if (carrier < 25000 || carrier > 150000)
> return -EINVAL;
>
> There are also examples where 0 has a special meaning (to be fair not
> with this function). Example:
> cfsetospeed() ... The zero baud rate, B0, is used to terminate the connection.
>
> I have no clue who will use the 0 but ...
[...]
If an ioctl is defined for a whole class of devices then it is perfectly
valid for the core code for that class to do (some) parameter validation
for the ioctl. As I'm not really familiar with LIRC I can't say for
sure that 0 is invalid, but if it is then driver writers should not
expect to be able to assign a driver-specific meaning to it. Consider
what would happen if the LIRC developers wanted to assign a generic
meaning to a value of 0 some time later.
Ben.
--
Ben Hutchings
Time is nature's way of making sure that everything doesn't happen at once.
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