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

[Greg KH]

On Mon, Apr 10, 2023 at 04:12:32PM -0700, Florian Fainelli wrote:
> 
> 
> 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?

I do not know, sorry.