Re: [PATCH] Documentation: firmware: Clarify firmware path usage

[Florian Fainelli]

On 4/10/2023 3:43 PM, Jonathan Corbet wrote:
> Florian Fainelli <f.fainelli@xxxxxxxxx> writes:
>
> > Newline characters will be taken into account for the firmware search
> > path parameter, warn users about that and provide an example using 'echo
> > -n' such that it clarifies the typical use of that parameter.
> >
> > Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
> > ---
> >   Documentation/driver-api/firmware/fw_search_path.rst | 9 +++++++--
> >   1 file changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/Documentation/driver-api/firmware/fw_search_path.rst b/Documentation/driver-api/firmware/fw_search_path.rst
> > index a360f1009fa3..d7cb1e8f0076 100644
> > --- a/Documentation/driver-api/firmware/fw_search_path.rst
> > +++ b/Documentation/driver-api/firmware/fw_search_path.rst
> > @@ -22,5 +22,10 @@ can use the file:
> >   
> >   * /sys/module/firmware_class/parameters/path
> >   
> > -You would echo into it your custom path and firmware requested will be
> > -searched for there first.
> > +You would echo into it your custom path and firmware requested will be searched
> > +for there first. Be aware that newline characters will be taken into account
> > +and may not produce the intended effects. For instance you might want to use:
> > +
> > +echo -n /path/to/script > /sys/module/firmware_class/parameters/path
> > +
> > +to ensure that your script is being used.
>
> So I have no problem with applying this, but I have to ask...might it
> not be better to fix the implementation of that sysfs file to strip
> surrounding whitespace from the provided path?  This patch has the look
> of a lesson learned the hard way; rather than codifying this behavior
> into a feature, perhaps we could just make the next person's life a bit
> easier...?

I was not sure whether it was on purpose or not, Greg, will we break 
anyone's use case if we strip off \n from the firmware path passed via 
sysfs?
--
Florian