Re: udev keymaps: support for force_release quirk

[Johannes Stezenbach <js@sig21.net>]

On Sat, Nov 28, 2009 at 11:14:54AM -0800, Greg KH wrote:
> On Thu, Nov 26, 2009 at 06:39:12PM +0100, Johannes Stezenbach wrote:
> > 
> > (please keep me Cc'd, I'm not subscribed)
> > 
> > following existing practice I wanted to add a quirk
> > for the hotkeys of the Samsung N130 in the same way
> > as it was done for the NC10, but was informed that
> > this method is no longer accepted since the quirk can
> > be handled in userspace using the force_release
> > sysfs attribute introduced in 2.6.32-rc.
> 
> What specific quirk are you needing for the N130?  I have one here and
> it seems to work just fine.

Well, by default most of the Fn keys have no keycode assigned,
so no problem except that the Fn keys don't work.

[  163.138031] atkbd.c: Unknown key pressed (translated set 2, code 0xf9 on isa0060/serio0).
[  163.138052] atkbd.c: Use 'setkeycodes e079 <keycode>' to make it known.
[  164.721926] atkbd.c: Unknown key pressed (translated set 2, code 0xf7 on isa0060/serio0).
[  164.721947] atkbd.c: Use 'setkeycodes e077 <keycode>' to make it known.
etc.

When I add the N130 in /lib/udev/rules.d/95-keymap.rules then
they keycodes get assigned, but some of the keys don't
generate release events, which can cause an endless stream
of keyevents in X, you can see them with xev (happens only
the first time a key is pressed, after that that key is dead
since there is no release event in between; the stream of events
stops when any opther key is pressed).  This makes e.g. the
backlight control keys useless.

For Fn-F4 the behaviour is that the keyboard goes dead in X,
you need to switch to the Linux console and back to X to revive it.
Maybe because it generates FocusOut events, no idea what
X is doing here:

FocusOut event, serial 33, synthetic NO, window 0x2800001,
    mode NotifyGrab, detail NotifyAncestor

FocusIn event, serial 33, synthetic NO, window 0x2800001,
    mode NotifyUngrab, detail NotifyAncestor

KeymapNotify event, serial 33, synthetic NO, window 0x0,
    keys:  33  0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   
           0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   0   

(the keycode assigned to Fn-F4 is KEY_SWITCHVIDEOMODE)

All this isn't new, the same issues existed for the NC10 and were
fixed by adding the force_release quirk.


Thanks
Johannes