Re: [PATCH net v2 2/2] ptp: idt82p33: implement double dco time correction

From: Jakub Kicinski
Date: Fri Sep 17 2021 - 17:06:41 EST


On Fri, 17 Sep 2021 20:19:08 +0000 Min Li wrote:
> >
> > > @@ -29,6 +29,14 @@ module_param(phase_snap_threshold, uint, 0);
> > > MODULE_PARM_DESC(phase_snap_threshold,
> > > "threshold (1000ns by default) below which adjtime would ignore");
> > >
> > > +static bool delayed_accurate_adjtime = false;
> > > +module_param(delayed_accurate_adjtime, bool, false);
> > > +MODULE_PARM_DESC(delayed_accurate_adjtime,
> > > +"set to true to use more accurate adjtime that is delayed to next
> > > +1PPS signal");
> >
> > Module parameters are discouraged. If you have multiple devices on the
> > system module parameters don't allow setting different options depending
> > on device. Unless Richard or someone else suggests a better API for this
> > please use something like devlink params instead (and remember to
> > document them).
> >
> > > +static char *firmware;
> > > +module_param(firmware, charp, 0);
>
> Yes, this was suggested by Richard back then

> On Fri, Jun 25, 2021 at 02:24:24PM +0000, Min Li wrote:
> > How would you suggest to implement the change that make the new driver behavior optional?
> I would say, module parameter or debugfs knob.

Aright, in which case devlink or debugfs, please.

> > What's the point of this? Just rename the file in the filesystem.
>
> We use this parameter to specify firmware so that module can be autoloaded
> /etc/modprobe.d/modname.conf

Sorry, I don't understand. The firmware is in /lib/firmware.
Previously you used a card coded name (whatever FW_FILENAME
is, "idt82p33xxx.bin"?). This patch adds the ability to change
the firmware file name by a module param.

Now let me repeat the question - what's the point of user changing
the requested firmware name if they can simply rename the file?