Re: [PATCH] firmware: add a function to load optional firmware v2

[Arend van Spriel]

On 3/13/2018 5:46 PM, Kalle Valo wrote:
> "Luis R. Rodriguez" <mcgrof@xxxxxxxxxx> writes:
>
> > On Tue, Mar 13, 2018 at 03:16:34PM +0200, Kalle Valo wrote:
> > > "Luis R. Rodriguez" <mcgrof@xxxxxxxxxx> writes:
> > >
> > > > > +/**
> > > > > + * request_firmware_optional: - request for an optional fw module
> > > > > + * @firmware_p: pointer to firmware image
> > > > > + * @name: name of firmware file
> > > > > + * @device: device for which firmware is being loaded
> > > > > + *
> > > > > + * This function is similar in behaviour to request_firmware(), except
> > > > > + * it doesn't produce warning messages when the file is not found.
> > > > > + **/
> > > > > +int
> > > > > +request_firmware_optional(const struct firmware **firmware_p, const char *name,
> > > > > +                         struct device *device)
> > > > > +{
> > > > > +       int ret;
> > > > > +
> > > > > +       /* Need to pin this module until return */
> > > > > +       __module_get(THIS_MODULE);
> > > > > +               ret = _request_firmware(firmware_p, name, device, NULL, 0,
> > > > > +                               FW_OPT_UEVENT | FW_OPT_NO_WARN );
> > > > > +       module_put(THIS_MODULE);
> > > > > +       return ret;
> > > > > +}
> > > > > +EXPORT_SYMBOL(request_firmware_optional);
> > > >
> > > > New exported symbols for the firmware API should be EXPORT_SYMBOL_GPL().
> > >
> > > To me the word optional feels weird to me. For example, in ath10k I
> > > suspect we would be only calling request_firmware_optional() with all
> > > firmware and not request_firmware() at all.
> > >
> > > How about request_firmware_nowarn()? That would even match the
> > > documentation above.
> >
> > _nowarn() works with me. Do you at least want the return value to give
> > an error value if no file was found? This way the driver can decide
> > when to issue an error if it wants to.
>
> Yes, it would be very good to return the error value to ath10k. That way
> we can give a proper error message to the user if we can't find a
> suitable firmware image.

I fully agree with the _nowarn() and returning an error. However, the 
firmware_p parameter (btw. do we really want the _p postfix?) is an 
output parameter which will be null in case of an error so do you really 
need a specific error code for the proper error message.

Regards,
Arend