I don't think you're correct at all in diagnosing that the problem
_isn't_ evdev. Making a few code modifications to the evdev driver to
account for the odd scancode reporting fixes it right up, even if the
volume control isn't as smooth as the windows version is. This
definitely indicates that the problem is (at least resolvable) in evdev.
I think I'm repeating myself, but I'll explain basically how the
scancode works on a normal keyboard key:
1) The keyboard (hardware) reports a scan-code indicating that the key has gone
_down_. This indicates which physical key was pressed to the software.
2) The 'driver' software translates the scan-code to the correct key-press in
the system locale and reports it to the shell/x-server/etc as a 'key event'.
3) The driver code waits a specific amount of time for another scan-code,
indicating that the key has gone _up_. When this is not received, it sends
another key 'event'.
4) Finally, the key is released, and the keyboard reports a scan-code
indicating that they key has gone _up_. The driver stops paying attention, as
it knows no (further) auto-repeat is required.
The problem is that when keyboards with media keys were first created,
there wasn't an explicit media keys standard- many OEMs provided their
own drivers. These keyboards, as often as not, did not bother to send
key-up events for their media keys. After all, keys like "stop",
"eject", "play', and etc. didn't really necessitate knowing when the key
was released, only when it was pressed.
When the media key format became more standardized, both the windows
drivers and the original X 'kbd' driver made a modification to their
code, which automatically injected a key-up directly after a key-down
for any media key. This 'hack' essentially turned of auto-repeat for
media keys.
Up until Hardy Heron, Ubuntu utilized the older X 'kbd' driver- so you
may notice that your volume keys work fine there. However, in the newer
versions, the 'evdev' driver is utilized instead, which lacks the
fundamental media-key-norepeat hack.
When I have time, I'll work on a similar hack for evdev- I have a
prototype running on my machine (and several other users machines) that
works perfectly, but I haven't had time to smooth out a few things (like
the fact that this makes the volume 'keys' extremely oversensitive on
the volume wheels of the U300 series.)
** Changed in: linux (Ubuntu)
Status: Confirmed => In Progress
** Changed in: linux (Ubuntu)
Assignee: (unassigned) => ktemkin (kyle-ktemkin)
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Volume control wheel on laptop is sticking in ubuntu
https://bugs.launchpad.net/bugs/271706
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