[PATCH 2/4] xserver: limit the kernel subsystems we look for devices in

[Peter Hutterer]

On Wed, Aug 03, 2011 at 10:04:08AM +0200, Michael Thayer wrote:
> On Wed, 2011-08-03 at 09:00 +1000, Peter Hutterer wrote:
> > On Mon, Aug 01, 2011 at 11:18:48PM +0200, Michael Thayer wrote:
> > > On Thu, 2011-07-21 at 09:40 +1000, Peter Hutterer wrote:
> > > > On Wed, Jul 20, 2011 at 05:52:16AM -0700, Dan Nicholson wrote:
> > > > > On Mon, Jul 18, 2011 at 12:17 PM, Lennart Poettering
> > > > > <lennart at poettering.net> wrote:
> > > > > > Don't enumerate/monitor all devices of the system (since that can be
> > > > > > quite a few), but limit our search to devices from the "input"
> > > > > > subsystem, as well as the "tty" subsystem (to cover Wacom tablets).
> > > > > >
> > > > > > This should make X start up a bit faster and reduce the number of
> > > > > > unnecessary wake-ups of the X server.
> > > > > > ---
> > > > > >  config/udev.c |    7 +++++++
> > > > > >  1 files changed, 7 insertions(+), 0 deletions(-)
> > > > > >
> > > > > > diff --git a/config/udev.c b/config/udev.c
> > > > > > index 5ac52a1..0763cc9 100644
> > > > > > --- a/config/udev.c
> > > > > > +++ b/config/udev.c
> > > > > > @@ -281,6 +281,9 @@ config_udev_init(void)
> > > > > >     if (!udev_monitor)
> > > > > >         return 0;
> > > > > >
> > > > > > +    udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, "input", NULL);
> > > > > > +    udev_monitor_filter_add_match_subsystem_devtype(udev_monitor, "tty", NULL); /* For Wacom serial devices */
> > > > > > +
> > > > > >     if (udev_monitor_enable_receiving(udev_monitor)) {
> > > > > >         ErrorF("config/udev: failed to bind the udev monitor\n");
> > > > > >         return 0;
> > > > > > @@ -289,6 +292,10 @@ config_udev_init(void)
> > > > > >     enumerate = udev_enumerate_new(udev);
> > > > > >     if (!enumerate)
> > > > > >         return 0;
> > > > > > +
> > > > > > +    udev_enumerate_add_match_subsystem(enumerate, "input");
> > > > > > +    udev_enumerate_add_match_subsystem(enumerate, "tty");
> > > > > > +
> > > > > >     udev_enumerate_scan_devices(enumerate);
> > > > > >     devices = udev_enumerate_get_list_entry(enumerate);
> > > > > >     udev_list_entry_foreach(device, devices) {
> > > > > 
> > > > > Last time this came up, we were a little uneasy about limiting the
> > > > > subsystems. I guess this should work for devices we care about, and
> > > > > any future input devices should fall under the input subsystem (I
> > > > > hope). One thing we could use help on in upstream udev is marking the
> > > > > appropriate serial devices with ID_INPUT* in
> > > > > 60-persistent-input.rules. I'm cc'ing Thomas since he was the one who
> > > > > originally requested that we not just filter to input.
> > > > 
> > > > At this point, all input devices that I've seen* are either supported by the
> > > > kernel or are legacy serial devices that don't have a kernel driver (yet).
> > > > I think we'll be fine filtering for those two only.
> > > Sorry for the late response - I was rather behind on reading this list.
> > > I would greatly appreciate it if you could add the "misc" subsystem for
> > > the sake of the VirtualBox mouse integration.
> > 
> > Not that I know anything about the details, but can we make the VirtualBox
> > mouse integration appear in the input subsystem? that seems to be the better
> > fix here.
> Not (as far as I can see) without writing a proper kernel input driver -
> which is something I do intend to do as soon as possible, but I hadn't
> actually planned to do it immediately.  Of course if you say that
> enumerating "misc" is not acceptable to you then I will probably have to
> give it a priority boost.

imo it seems to be the better solution than just whitelisting "misc", which
at least partially defeats the purpose of restricting to input subsystems
only.

Cheers,
  Peter