Re: [linux-usb-devel] [PATCH] usb/hid: The HID Simple Driver Interface 0.3.2 (core)

[Dmitry Torokhov <dtor@insightbb.com>]

On Monday 09 October 2006 18:53, Anssi Hannula wrote:
> Dmitry Torokhov wrote:
> > On Sunday 08 October 2006 14:51, Anssi Hannula wrote:
> >> (I didn't get Dmitry's original mail, so replying here)
> >>
> >> raise.sail@gmail.com wrote:
> >>> Dmitry Torokhov wrote:
> >>>> Then there is issue with automatic loading of these sub-drivers. How
> >>>> do they get loaded? Or we force everything to be built-in making HID
> >>>> module very fat (like psmouse got pretty fat, but with HID prtential
> >>>> for it to get very fat is much bigger).
> >>>>
> >>>> The better way would be to split hid-input into a library module that
> >>>> parses hid usages and reports and is shared between device-specific
> >>>> modules that are "real" drivers (usb-drivers, not hid-sub-drivers).
> >> One possibility is to do that with symbol_request() and friends. That
> >> would not be pretty though, imho.
> >>
> >> DVB subsystem uses that currently to load frontend modules dynamically,
> >> see dvb_attach() and dvb_frontend_detach() in
> >> drivers/media/dvb/dvb-core/dvbdev.h and
> >> drivers/media/dvb/dvb-core/dvb_frontend.c.
> >>
> > 
> > Unfortunately this does not quite work when hid is built-in and the rest
> > are modules :(
> > 
> 
> How so? I see nothing obvious.
> 

If hid (and hcd) is compiled in it will try binging to devices before
userspace is up and symbol_request will not work. You could try
playing with initramfs but it is kind of a hassle.

-- 
Dmitry