Re: AW: AltGr key mostly fires an additional CONTROL key

[Jon TURNEY <jon.turney@dronecode.org.uk>]

>> The actual issue here is that Windows apparently inserts a fake Ctrl-L
>> keypress/release when AltGr is pressed/released (except when the keyboard
>> layout is US).  I have never found any documentation of this behavior, and
>> I've no idea why it does this.
>>
>> There is some code in the X server which attempts to detect and discard these
>> fake keypress/release events, but it not working reliably for some people has
>> been reported a few times, but I've never been able to reproduce the problem
>> or get to the bottom of what causes it.
>>
>> If you are willing to help, I've put together a test build with some extra
>> debugging at [1].  If you could run that with '-logverbose 3' as before and
>> attach the output, that would be helpful.
>>
>> [1] ftp://cygwin.com/pub/cygwinx/XWin.20110801-git-2d9f9305cb559907.exe.bz2
>>
> no problem - here we go:
> The logs are attached.
>
> This is what I did:
>
> 1. /bin/startxwin -- XWin.20110801-git-2d9f9305cb559907.exe -emulate3buttons 100 -logverbose 3
> 2. It took me more attempts than usual to reproduce it, therefore the interesting part will be at the end of the log.
> 3. I manually killed the X-Server and took the log.
> 4. XWin.0.log is the full log of the session.
> 5. xev.txt: I have taken only the "interesting" part.
>
> My session in detail:
>
> I pressed several times AltGr and Q, nothing special, I get "@" (it doesn't happen always - just then and when).
> I hold down AltGr for 2 seconds ... I play around.
> Then I get into the bug:
> I press AltGr and Q, then release both keys: I get CHAR 00.
> I just hit key A and instead of "a" I get CHAR 01 = CONTROL-A.
> I just hit key C and instead of "c" I get CHAR 03 = CONTROL-C.
> Then I (first time) hit the real CONTROL key to unlock that situation. In the xev-log you see only(!) a ReleaseEvent at that point.
> Then I press AltGr and Q again and I get CHAR HEX 40 = letter "@".
> I hit key A and get "a".

Thanks for the logs, that was very useful.

I still can't reproduce this (although holding AltGr down to make it 
autorepeat seems the best way to try to do that).  It is a timing issue with 
the keypress/release messages so it might be sensitive to CPU speed, or 
perhaps you have some software installed which looks at keypress/release 
messages and changes the timing?

I've had a go at fixing it.  Can you please try the build I've uploaded at [1] 
and see if it still shows the problem for you?

[1] ftp://cygwin.com/pub/cygwinx/XWin.20110803-git-a493c0465e56ce0b.exe.bz2

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