usb/137189: [usb][patch] create and use sysctl nodes for HID
Hans Petter Selasky
hselasky at c2i.net
Fri Jul 31 08:20:04 UTC 2009
The following reply was made to PR usb/137189; it has been noted by GNATS.
From: Hans Petter Selasky <hselasky at c2i.net>
To: rea-fbsd at codelabs.ru
Cc: bug-followup at freebsd.org,
freebsd-usb at freebsd.org
Subject: Re: usb/137189: [usb][patch] create and use sysctl nodes for HID report descriptors
Date: Fri, 31 Jul 2009 09:19:03 +0200
On Thursday 30 July 2009 22:38:12 Eygene Ryabinkin wrote:
> Hans Petter, good day.
> Tue, Jul 28, 2009 at 07:40:27PM +0400, Eygene Ryabinkin wrote:
> > HPS wrote:
> > > > Why do you dislike the sysctl approach? It is simple and reliable.
> > >
> > > It's duplicating access to data. There is not that much wrong about
> > > it, except it will not work if the device is of another kind. I.E. you
> > > would have to patch the HID sysctl node into every driver accessing
> > > HID descriptors?
> > Just now -- yes, I'll need it. But probably I can move this
> > functionality into the USB bus level -- it will automatically create
> > this sysctl node for all HID children and will dispose it on the detach.
> > usb_probe_and_attach() is a candidate for such functionality. Will it
> > be bad?
> OK, attached is the reworked version of the sysctl patch: it now creates
> the needed nodes automatically (though they still can be created by
> explicit call from the driver, as in uhid(4)). As a bonus, kernel got the
> ability to install per-USB class post-attach and pre-detach handlers, so
> we can do some class-specific things for every driver. What do you think
> of it?
I think it's too much code to doo too little, and adds extra complexity, and
that doing this via libusb would be much more generic.
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