ports/131124: x11/xorg - New xorg 7.4 hangs until mouse is moved when AllowEmptyInput turned off

[Robert Noland]

On Fri, 2009-02-06 at 16:27 -0500, Joe Marcus Clarke wrote:
> Jung-uk Kim wrote:
> > [Sorry for spamming y'all but I thought it is very important that 
> > everyone understands the situation clearly.]
> > 
> > On Thursday 05 February 2009 11:50 am, Serge Shilov wrote:
> >> The following reply was made to PR ports/131124; it has been noted
> >> by GNATS.
> >>
> >> From: Serge Shilov <serguei.shilov at gmail.com>
> >> To: bug-followup at freebsd.org,
> >>  xelah-freebsd-pr at xelah.com
> >> Cc:
> >> Subject: Re: ports/131124: x11/xorg - New xorg 7.4 hangs until
> >> mouse is moved when AllowEmptyInput turned off Date: Thu, 5 Feb
> >> 2009 19:40:29 +0300
> >>
> >>  I perform some experiments. Results is here.
> >>
> >>  I. Test other mice .
> >>  The 1st is
> >>  ums0: <A4Tech RF USB Mouse, class 0/0, rev 1.10/0.01, addr 2> on
> >> uhub0 ums0: 8 buttons and Z dir.
> >>
> >>  and the 2nd is
> >>  ums0: <Logitech Optical USB Mouse, class 0/0, rev 2.00/3.40, addr
> >> 2> on uhub0 ums0: 3 buttons and Z dir.
> >>
> >>  Bug still exist
> >>
> >>  II. Test direct connection mouse without hub.
> >>
> >>  Bug still exist.
> >>
> >>  Resume: It's not mice or hub or connection-via-hub problem. (But
> >> it may be some usb host problem)
> >>
> >>  III. Hot plug out and plug in mouse in X environment
> >>
> >>  After plug in mouse gehaviour BEGAN CONVENTIONAL. This can be
> >> recommended as workaround.
> >>
> >>  Notice:
> >>  1. After plug out mouse cursor may still disappeared. In this case
> >> you can switch to VT0-VT7 terminals, move mouse and switch back to
> >> X session. 2. This advice is provided 'as is' without any
> >> warranties of usefulness, capacity to work with your hardware or
> >> software and other sorts of warranties.
> >>
> >>  IV. After hot  X session restart (without OS and hardware restart)
> >> mouse still work.
> >>
> >>  V. Other cases:
> >>  Hot plug out and plug in mouse in text mode environment before
> >> start X session.
> >>  Start OS mouseless and plug in mouse before or after start X
> >> session. Hot OS restart after my workaround appliing.
> >>
> >>  In all this cases mouse behaviour was still buggy.
> >>
> >>  I'll be glad if my info help to resolve this problem.
> > 
> > 
> > A short answer:
> > 
> > Please remove "AllowEmptyInput" from your xorg.conf.
> > 
> > A longer answer:
> > 
> > http://docs.freebsd.org/cgi/mid.cgi?200902041908.50270.jkim
> > 
> > A technical answer:
> > 
> > Some devices are safe to be opened multiple times and shared by 
> > different input drivers (e.g., Linux evdev, I think) and some devices 
> > are not (e.g., our sysmouse).
> > 
> > Possible solutions (for ports maintainers):
> > 
> > - When hald probes mice, exclude all moused users 
> > (e.g., /dev/psm0, /dev/ums1, ...) from x11_driver and create a pseudo 
> > device UDI for /dev/sysmouse and set x11_driver property if moused(8) 
> > is running and /dev/sysmouse is not being used by Xserver.  If 
> > Xserver tries to open /dev/sysmouse, then the UDI has to be removed 
> > immediately.  When Xserver closes /dev/sysmouse, the fake UDI has to 
> > be restored immediately.
> > 
> > - Before Xserver starts auto-adding process, send a hint message to 
> > hald that the device is configured and enabled by static user 
> > configuration if CONFIG_HAL is defined and "AutoAddDevices" or 
> > "AutoEnableDevices" is on.  hald (i.e., FreeBSD mouse prober) 
> > excludes all sysmouse users from x11_driver and sends ACK/NACK 
> > message.  Then, Xserver continues/stops auto-adding process depending 
> > on it.
> > 
> > - Implement an ioctl command for sysmouse to report actual devices 
> > that it is controlling.  Let each input driver veto automagic 
> > configuration process if it is being used or unsafe.
> > 
> > - Some combinations of the above...
> > 
> > The first solution is the least intrusive but it is not bulletproof 
> > because of an unavoidable race condition.  The second solution is 
> > IMHO, a correct way but it requires Xserver change first.  The third 
> > solution is too platform-specific and it requires significant (and 
> > ugly) hacks for Xserver and input drivers, I think.
> > 
> > Any more ideas?
> 
> What about modifying the sysmouse driver to more gracefully handle
> multiple open attempts (e.g. fail on subsequent attempts).  What effect
> would that have on X?

I think X would be fine with that... That is what happens now with the
psm and ums devices.  At least if they are statically configured and
hald is in use.

robert.

> Joe
> 
> -- 
> Joe Marcus Clarke
> FreeBSD GNOME Team	::	gnome at FreeBSD.org
> FreeNode / #freebsd-gnome
> http://www.FreeBSD.org/gnome
-- 
Robert Noland <rnoland at FreeBSD.org>
FreeBSD
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