modifiers key get stuck (alt key generally) about xpra

[totaam]

2011-08-18 17:25:50: antoine commented

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To those who are experiencing this, can you please post details:

• svn/version
• which distro version for both client and server
• keyboard layout / input method
• output from setxkbmap -query and setxkbmap -print
• anything else that might be relevant
  Thanks

[totaam]

2011-08-21 17:03:32: lindi commented

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• SVN r135
• debian squeeze (stable) on amd64
• finnish keyboard
• sid setxkbmap -query

rules:      evdev
model:      pc105
layout:     fi,latam
variant:    ,
options:    grp:alts_toggle

• setxkbmap -print

xkb_keymap {
	xkb_keycodes  { include "evdev+aliases(qwerty)"	};
	xkb_types     { include "complete"	};
	xkb_compat    { include "complete"	};
	xkb_symbols   { include "pc+fi+latam:2+inet(evdev)+level3(ralt_switch_for_alts_toggle):1+level3(ralt_switch_for_alts_toggle):2+group(alts_toggle)"	};
	xkb_geometry  { include "pc(pc105)"	};
};

Steps to reproduce:

1. xpra start --no-daemon --start-child gnome-terminal --exit-with-children :9 -d all > xpra.server.txt 2>&1
2. xpra -d all attach :9 > xpra.client.txt 2>&1
3. wait for gnome-terminal to appear, move mouse over it
4. type a, b, c, d, e, f
5. hit alt-tab to switch to some other window
6. hit alt-tab again to switch back to gnome-terminal
7. type f

Expected results:
4) & 7) gnome-terminal reads "abcdeff"

Actual results:
4 & 7) gnome-terminal reads "abcdef" and the File menu is open (since alt+F opens it)

More info:

1. xpra.server.txt and xpra.client.txt are attached.

[totaam]

2011-08-21 17:03:50: lindi uploaded file xpra.server.txt.gz (65.4 KiB)

[totaam]

2011-08-21 17:03:59: lindi uploaded file xpra.client.txt.gz (36.4 KiB)

[totaam]

2011-08-21 17:06:51: lindi commented

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Oh and yes, I'm using gnome.

Also, keys getting stuck cause a lot of weird effects. For example starting xpra can take minutes. Apparently this is because of xmodmap:

$ xpra start --no-daemon --use-display :7
found /home/lindi/xpra-install/amd64/v0.0.7.22-60-ga4aabe0/
Xlib:  extension "RANDR" missing on display ":7.0".
Xlib:  extension "RANDR" missing on display ":7.0".
Xlib:  extension "RANDR" missing on display ":7.0".
Missing window or missing property or wrong property type WM_TRANSIENT_FOR (window)
Missing window or missing property or wrong property type _NET_WM_STRUT_PARTIAL (strut-partial)
Missing window or missing property or wrong property type _NET_WM_STRUT (strut)
Missing window or missing property or wrong property type _NET_WM_STRUT_PARTIAL (strut-partial)
Missing window or missing property or wrong property type _NET_WM_STRUT (strut)
xmodmap:  please release the following keys within 2 seconds:
    Control_L (keysym 0xffe3, keycode 37)
    d (keysym 0x64, keycode 40)
    KP_Up (keysym 0xff97, keycode 80)
xmodmap:  please release the following keys within 4 seconds:
    Control_L (keysym 0xffe3, keycode 37)
    d (keysym 0x64, keycode 40)
    KP_Up (keysym 0xff97, keycode 80)
xmodmap:  please release the following keys within 8 seconds:
    Control_L (keysym 0xffe3, keycode 37)
    d (keysym 0x64, keycode 40)
    KP_Up (keysym 0xff97, keycode 80)
xmodmap:  please release the following keys within 16 seconds:
    Control_L (keysym 0xffe3, keycode 37)
    d (keysym 0x64, keycode 40)
    KP_Up (keysym 0xff97, keycode 80)
xmodmap:  please release the following keys within 32 seconds:
    Control_L (keysym 0xffe3, keycode 37)
    d (keysym 0x64, keycode 40)
    KP_Up (keysym 0xff97, keycode 80)
xmodmap:  unable to set modifier mapping, keyboard problem
Randr not supported: X server does not support required extension Randr
randr enabled: False

xpra is ready.

[totaam]

2011-08-24 22:11:49: lindi commented

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$ grep key-action xpra.client.txt 
writing ['key-action', 1, 'a', True, [], 97, 'a', 38]
writing ['key-action', 1, 'a', False, [], 97, 'a', 38]
writing ['key-action', 1, 'b', True, [], 98, 'b', 56]
writing ['key-action', 1, 'b', False, [], 98, 'b', 56]
writing ['key-action', 1, 'c', True, [], 99, 'c', 54]
writing ['key-action', 1, 'c', False, [], 99, 'c', 54]
writing ['key-action', 1, 'd', True, [], 100, 'd', 40]
writing ['key-action', 1, 'd', False, [], 100, 'd', 40]
writing ['key-action', 1, 'e', True, [], 101, 'e', 26]
writing ['key-action', 1, 'e', False, [], 101, 'e', 26]
writing ['key-action', 1, 'f', True, [], 102, 'f', 41]
writing ['key-action', 1, 'f', False, [], 102, 'f', 41]
writing ['key-action', 1, 'Alt_L', True, [], 65513, '', 64]
writing ['key-action', 1, 'Tab', False, [], 65289, '', 23]
writing ['key-action', 1, 'f', True, [], 102, 'f', 41]
writing ['key-action', 1, 'f', False, [], 102, 'f', 41]

shows pretty clearly that the problem is client-side. Client never tells the server that I have released Alt.

[totaam]

2011-08-24 23:31:52: lindi uploaded file release-keys-on-unfocus1.diff (2.1 KiB)

proof-of-concept to fix the bug

[totaam]

2011-08-24 23:32:48: lindi commented

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Since this bug really interferes with my ability to use the computer here's a proof-of-concept that works for me(tm) but definitely needs futher polishing.

[totaam]

2011-08-24 23:56:38: lindi commented

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Seems this is still not sufficient. At least quassel opens the menu if I press alt, release alt and then hit f. So, sending release event for alt is not enough.

[totaam]

2011-08-25 00:01:13: lindi uploaded file release-keys-on-focus1.diff (2.2 KiB)

another prototype to fix the problem

[totaam]

2011-08-25 00:01:43: lindi commented

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It seems that if I send the release events when the window receives focus again then applications correctly handle this.

[totaam]

2011-08-25 02:42:31: antoine changed status from new to accepted

[totaam]

2011-08-25 02:42:31: antoine commented

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The problem is not solved client-side at the moment (and I'm not sure it should be either).
The code you are looking for is _make_keymask_match in server.py
It fires whenever we get keypresses and is meant to ensure the modifiers set on the server match the ones set in the client. Not sure why it stopped working since the keymap changes but now that I have your keymap details I should be able to reproduce.

[totaam]

2011-08-25 09:07:33: lindi commented

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Also non-modifiers get stuck so I don't see how that code would help alone?

[totaam]

2011-08-25 15:10:29: antoine commented

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In fact, the _make_keymask_match must be server-side, as the client has no way of knowing what state the session is in at the moment, so this is the best place to do it.

Can you give me steps for getting non-modifier keys to get stuck? Do you get that often?

[totaam]

2011-08-25 15:36:53: antoine commented

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We now apply the full keymap, using 'xmodmap -pke' to grab all the raw keyval mappings from the client (if available) - done in r137

We now also clear all modifiers when a new client attaches to a session (r138), this should fix the xmodmap timeout (which I have not seen myself before).

Now, on to the alt-key gets stuck proper...

[totaam]

2011-08-25 15:36:53: antoine

[totaam]

2011-08-25 16:02:21: lindi commented

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Yes, I often have one of the arrow keys stuck. You can imagine that this leads to rather bad behavior in different applications :-)

[totaam]

2011-08-25 16:11:39: antoine commented

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r139 batches the keymap updates and ensures we don't get the same xmodmap timeouts when keymap-changed fires: we also send the client's current modifiers and set them.

I just can't get the alt-tab to get stuck, despite setting my keyboard to as per comment:2

[totaam]

2011-08-25 16:34:32: lindi commented

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Here's how the Up arrow gets stuck with r135:

$ xpra start --no-daemon --start-child gnome-terminal --exit-with-children :9 -d all > xpra.server.txt 2>&1
$ xpra -d all attach :9 > xpra.client.txt 2>&1
# hold the up arrow down
#  notice how the shell is going through all your history entries
# hit alt-tab
# hit alt-tab again
$ grep -E "(key-action|focus)" xpra.client.txt
writing ['focus', 1]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Up', True, [], 65362, '', 111]
writing ['key-action', 1, 'Alt_L', True, [], 65513, '', 64]
writing ['key-action', 1, 'Up', True, ['meta'], 65362, '', 111]
writing ['key-action', 1, 'Up', True, ['meta'], 65362, '', 111]
writing ['focus', 0]
writing ['focus', 1]
writing ['key-action', 1, 'Alt_L', True, [], 65513, '', 64]
writing ['focus', 0]

The client never tells the server that I released the up arrow!

[totaam]

2011-08-25 18:38:02: antoine commented

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r142 ensures that we clear the keys that are currently pressed when we lose focus, we also send the list of modifiers when we gain focus so we can set them correctly again if any are set.
This should fix the problem with "arrow keys get stuck", but probably not "alt gets stuck"...
Please confirm if this is an improvement for you.

[totaam]

2011-08-31 19:15:30: antoine uploaded file squeeze-finnish-keyboard-test.png (67.0 KiB)

testing the alt-tab issue on Debian Squeeze (screenshot)

[totaam]

2011-08-31 19:17:18: antoine commented

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I've just tested on r142 on a fresh install of Debian Squeeze, as you can see on the screenshot the keyboard is set to finnish. I've tried and tried again to reproduce the bug and I just can't do it! :(

Do I need to launch another VM with Debian Sid on it?

[totaam]

2011-09-07 10:33:31: antoine commented

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Another commit related to stuck keys: clear keys when client disconnects and ensure we don't re-set them by ignoring any packets arriving in the new "closing" state.

[totaam]

2011-09-07 10:53:15: antoine commented

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Finally, this is for the very unusual case where the server is control-Ced from within the client (via screen) and we end up with the control key stuck:
r159 always clears the modifiers on startup so users can re-attach to an existing display (with -use-display=) and not have xmodmap timeouts.

[totaam]

2011-09-23 15:49:41: antoine changed priority from major to minor

[totaam]

2011-09-23 15:49:41: antoine

[totaam]

2011-09-23 15:49:41: antoine commented

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r187 improves this further
Although I have seen the 'C' key getting stuck when I ^C the server from within xpra via screen, this is a unusual scenario and should no longer cause timeouts when re-starting the server.
Lowering priority, please raise again if any of this is wrong.

[totaam]

2011-09-23 15:49:41: totaam

[totaam]

2011-12-08 13:44:56: totaam changed status from accepted to closed

[totaam]

2011-12-08 13:44:56: totaam changed resolution from ** to fixed

[totaam]

2011-12-08 13:44:56: totaam commented

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Not heard anything for 3 months, closing.

[totaam]

2012-02-20 20:13:14: totaam