Calling all hotkey expertise...

Fri Feb 18 00:15:06 UTC 2011

Em Qui, 2011-02-17 às 12:31 +0000, Colin Ian King escreveu:
> Thanks Herton,
> 
> On Thu, 2011-02-10 at 19:58 -0200, Herton Ronaldo Krzesinski wrote:
> > Em Qui, 2011-02-10 às 21:00 +0000, Colin Ian King escreveu:
> > From what I remember and from experience (correct me if I say something
> > wrong), vendors usually implement hotkeys:
> > - using a WMI interface, where a driver needs to be written. The driver
> > receives a WMI notification and calls wmi_evaluate_method (WMXX) to get
> > the response/data so if the event is a hotkey it gets a code and
> > translates it to input layer. It's a lot easier if the vendor gives
> > information on its WMI implementation, as by nature of ACPI-WMI every
> > vendor can choose what parameters/format to accept on WMI methods etc.
> 
> Yep, good one and becoming more frequent. As documented here:
> https://wiki.ubuntu.com/Kernel/Reference/WMI
> 
> Personally, I'd like to write a MOF disassembler to extract a high level
> view of the WMI configuration from the WQxx objects rather than by
> poking around and figuring out how these work by trial-and-error...
> when I have time.. :-)

Nice, would be great to have such tool.

I remembered now, there is also the paramters of wmi module that were
added "recently" to the kernel (2.6.35) and are very useful, specially
in detecting if the machine has wmi objects and if we are receiving
things through wmi.
wmi.debug_dump_wdg=1 to list wmi interfaces
wmi.debug_event=1 to show on dmesg events we received

Especially when hotkeys doesn't work, is useful to enable debug_event
because if it's implemented by wmi, when we press the hotkey information
will appear on dmesg. May be it isn't useful for vendor documentation,
but is useful to us and users when hotkeys doesn't work and we want to
check if it's done by wmi or testing when developing.

> > - sending codes directly via the keyboard controller (so implemented
> > directly in embedded controller, also some people call it as keyboard
> > bios, but anyway I think should be on ec firmware). So kernel directly
> > receive keyboard codes on keyboard input device, no need to extra
> > driver, but many times the codes have to be remaped on user space to the
> > real key code meaning/value (udev keymaps)
> 
> I wonder if there are any standard configurations we can recommend for
> this
> method of hotkeys?  Any ideas anyone?

Well, I think at least use the common known 0xe0 scan codes for
multimedia etc. If we look at some of the keymaps in udev, there are
some multimedia keys which could have been reported using a common known
scancode which atkbd recognizes (the so called "Windows Multimedia Scan
Codes"). But instead the vendor chose a non-standard scan code, which
have to be remmaped.

I did a test program (attached for reference) which prints current
extended scan codes which atkbd translates to input layer. Here I paste
only the relevant entries, first column is the key sent to user space
(last column its respective numeric value):

E0 Scan Code Set 1 - scancodes

PreviousSong - key, press == 0xe0 0x10, release == 0xe0 0x90, ScanCode == 0x90, keycode == 165
    NextSong - key, press == 0xe0 0x19, release == 0xe0 0x99, ScanCode == 0x99, keycode == 163
        Mute - key, press == 0xe0 0x20, release == 0xe0 0xa0, ScanCode == 0xa0, keycode == 113
        Calc - key, press == 0xe0 0x21, release == 0xe0 0xa1, ScanCode == 0xa1, keycode == 140
   PlayPause - key, press == 0xe0 0x22, release == 0xe0 0xa2, ScanCode == 0xa2, keycode == 164
      StopCD - key, press == 0xe0 0x24, release == 0xe0 0xa4, ScanCode == 0xa4, keycode == 166
  VolumeDown - key, press == 0xe0 0x2e, release == 0xe0 0xae, ScanCode == 0xae, keycode == 114
    VolumeUp - key, press == 0xe0 0x30, release == 0xe0 0xb0, ScanCode == 0xb0, keycode == 115
    HomePage - key, press == 0xe0 0x32, release == 0xe0 0xb2, ScanCode == 0xb2, keycode == 172
       Pause - key, press == 0xe0 0x45, release == 0xe0 0xc5, ScanCode == 0xc5, keycode == 119
       Pause - key, press == 0xe0 0x46, release == 0xe0 0xc6, ScanCode == 0xc6, keycode == 119
       Power - key, press == 0xe0 0x5e, release == 0xe0 0xde, ScanCode == 0xde, keycode == 116
       Sleep - key, press == 0xe0 0x5f, release == 0xe0 0xdf, ScanCode == 0xdf, keycode == 142
      WakeUp - key, press == 0xe0 0x63, release == 0xe0 0xe3, ScanCode == 0xe3, keycode == 143
      Search - key, press == 0xe0 0x65, release == 0xe0 0xe5, ScanCode == 0xe5, keycode == 217
   Bookmarks - key, press == 0xe0 0x66, release == 0xe0 0xe6, ScanCode == 0xe6, keycode == 156
     Refresh - key, press == 0xe0 0x67, release == 0xe0 0xe7, ScanCode == 0xe7, keycode == 173
        Stop - key, press == 0xe0 0x68, release == 0xe0 0xe8, ScanCode == 0xe8, keycode == 128
     Forward - key, press == 0xe0 0x69, release == 0xe0 0xe9, ScanCode == 0xe9, keycode == 159
        Back - key, press == 0xe0 0x6a, release == 0xe0 0xea, ScanCode == 0xea, keycode == 158
    Computer - key, press == 0xe0 0x6b, release == 0xe0 0xeb, ScanCode == 0xeb, keycode == 157
        Mail - key, press == 0xe0 0x6c, release == 0xe0 0xec, ScanCode == 0xec, keycode == 155
       Media - key, press == 0xe0 0x6d, release == 0xe0 0xed, ScanCode == 0xed, keycode == 226

E0 Scan Code Set 2 - scancodes

      Search - key, press == 0xe0 0x10, release == 0xe0 0x90, ScanCode == 0x90, keycode == 217
PreviousSong - key, press == 0xe0 0x15, release == 0xe0 0x95, ScanCode == 0x95, keycode == 165
   Bookmarks - key, press == 0xe0 0x18, release == 0xe0 0x98, ScanCode == 0x98, keycode == 156
     Refresh - key, press == 0xe0 0x20, release == 0xe0 0xa0, ScanCode == 0xa0, keycode == 173
  VolumeDown - key, press == 0xe0 0x21, release == 0xe0 0xa1, ScanCode == 0xa1, keycode == 114
        Mute - key, press == 0xe0 0x23, release == 0xe0 0xa3, ScanCode == 0xa3, keycode == 113
        Stop - key, press == 0xe0 0x28, release == 0xe0 0xa8, ScanCode == 0xa8, keycode == 128
        Calc - key, press == 0xe0 0x2b, release == 0xe0 0xab, ScanCode == 0xab, keycode == 140
     Forward - key, press == 0xe0 0x30, release == 0xe0 0xb0, ScanCode == 0xb0, keycode == 159
    VolumeUp - key, press == 0xe0 0x32, release == 0xe0 0xb2, ScanCode == 0xb2, keycode == 115
   PlayPause - key, press == 0xe0 0x34, release == 0xe0 0xb4, ScanCode == 0xb4, keycode == 164
       Power - key, press == 0xe0 0x37, release == 0xe0 0xb7, ScanCode == 0xb7, keycode == 116
        Back - key, press == 0xe0 0x38, release == 0xe0 0xb8, ScanCode == 0xb8, keycode == 158
    HomePage - key, press == 0xe0 0x3a, release == 0xe0 0xba, ScanCode == 0xba, keycode == 172
      StopCD - key, press == 0xe0 0x3b, release == 0xe0 0xbb, ScanCode == 0xbb, keycode == 166
       Sleep - key, press == 0xe0 0x3f, release == 0xe0 0xbf, ScanCode == 0xbf, keycode == 142
    Computer - key, press == 0xe0 0x40, release == 0xe0 0xc0, ScanCode == 0xc0, keycode == 157
        Mail - key, press == 0xe0 0x48, release == 0xe0 0xc8, ScanCode == 0xc8, keycode == 155
    NextSong - key, press == 0xe0 0x4d, release == 0xe0 0xcd, ScanCode == 0xcd, keycode == 163
       Media - key, press == 0xe0 0x50, release == 0xe0 0xd0, ScanCode == 0xd0, keycode == 226
      WakeUp - key, press == 0xe0 0x5e, release == 0xe0 0xde, ScanCode == 0xde, keycode == 143
       Pause - key, press == 0xe0 0x77, release == 0xe0 0xf7, ScanCode == 0xf7, keycode == 119
       Pause - key, press == 0xe0 0x7e, release == 0xe0 0xfe, ScanCode == 0xfe, keycode == 119

So, for example, if vendor implements keyboard sending by default Scan
Code Set 1 (Translated set 2 mode in atkbd), and he has a hotkey
Play/Pause, then instead of using an arbitrary code he should send the
raw scan code 0xe0 0x22 for press, 0xe0 0xa2 for release, as atkbd
already has a default mapping.

If vendor implements keyboard sending by default Scan Code Set 2, for
Play/Pause the codes should be 0xe0 0x34 / 0xe0 0xb4 (press/release).

I propose above based on documentation I found at
http://www.computer-engineering.org/ps2keyboard/ (explains about scan
codes etc.) and research I did today on atkbd code.

For keys which don't have scan code listed above, we can't do much, we
will have to remap and vendor choose some code, unless someone comes
with some standard for more scan code values, which then we can put into
atkbd keymaps.

To be more clear also, I tested to confirm with my notebook (reports
Scan Code Set 1) which send these standard multimedia scancodes, no
remapping needed. To check raw scan codes sent by keyboard, I did:
echo 0 > /sys/devices/platform/i8042/serio0/softraw
To disable the softraw mode so you can get the raw codes and use evtest:
evtest /dev/input/eventX

When I press the hotkey, I get the raw code, the emulated ScanCode
(index which atkbd uses to get the real input code from keycode array)
and the translated key code. This procedure of disabled softraw and
evtest I found very useful for testing. 

If anyones sees something missing or other issue please feel free to add
more information.

-- 
[]'s
Herton
-------------- next part --------------
A non-text attachment was scrubbed...
Name: test.c
Type: text/x-csrc
Size: 16533 bytes
Desc: not available
URL: <https://lists.ubuntu.com/archives/kernel-team/attachments/20110217/e3850fcf/attachment.c>