Re: [orca-list] Lightdm GTK greeter accessibility revisited

[Peter Vágner <pvdeejay gmail com>]

Hello,

Please rebuild from the same url if you are still free for testing
http://files.pvagner.tk/lightdm-gtk-greeter.tar.gz

I guess I've managed to make it work as we wish it to.

I assume processes started using g_spawn_async are better terminated 
using g_spawn_close_pid rather than using plain waitpid. Anyway I know 
nothing about all these libraries and their functions I have just been 
tinkering with lightdm until it started to work for me. What I did is 
inspired by the code I've seen when looking at the revision diffs. 
Please test if you like. If it's confirmed as working, I'll post the 
patch to the bug report Kyle has filed a while ago. The patch is very 
simple and it cleanly applies to both latest stable version as well as 
to the latest code found in the bzr trunk.

P.S. It's now also clear It's confirmed the issue is not in orca.

Greetings

Peter

On 03.12.2015 at 03:41 kendell clark wrote:
> hi
> Got it. I'll indeed download your pkgbuild. Congrats for looking into
> this, you got a great deal further than either kyle or I did, I'd pretty
> much given it up as a lost cause. Since you have done this, I'm
> determined to get this fixed. Joanie, would you be willing to look into
> this if we can figure out what's going on with orca, if it is indeed orca?
> Thanks
> Kendell clark
>
>
> On 12/02/2015 08:22 PM, Peter Vágner wrote:
> > Hello,
> >
> > I am sorry you are most likelly missunderstanding me.
> >
> > Please try downloading my PKGBUILD from
> > http://files.pvagner.tk/lightdm-gtk-greeter.tar.gz and please build it
> > as normal.
> >
> > Then make sure you do have screen reader configured and enabled in
> > /etc/lightdm/lightdm-gtk-greeter.conf
> > i.e. it contains something similar to this effect
> >
> > [greeter]
> > reader=orca
> > a11y-states=reader
> >
> > Of course it may contain more accessibility related and other
> > preferences you like.
> >
> > Then start it
> > sudo systemctl start lightdm
> >
> > and finally test that it really does work with my one line tweak I am
> > proposing in one of the comments to the Kyle's bug.
> >
> > However there is a new issue I am seeking to get some help with. When
> > the greeter is showing, orca is running you do have nice accessible
> > greeter session.
> > When you try to switch off screen reader at this point either by hitting
> > F4 or from the menu bar you will notice orca freezing.
> > In fact you can even see it freezing when doing
> > sudo killal orca
> > instead of using lightdm greeter feature to close it.
> >
> > Regarding sig term vs sig kill debate I have found a blogpost explaining
> > the differences at https://major.io/2010/03/18/sigterm-vs-sigkill/
> >
> > When looking into orca source code I can see a method which is called
> > when orca receives SIGTERM. It's shutdownOnSignal found at line 709 in
> > the file src/orca/orca.py . The very first thing orca does here is that
> > it should print a message saying 'ORCA: Shutting down and exiting due to
> > signal=%d' into its debug file. I haven't found this in the log thus I
> > think python is crashing here or something similar.
> >
> >
> >
> > Greetings
> >
> > Peter
> >
> >
> > On 02.12.2015 at 23:28 kendell clark wrote:
> > > hi
> > > I've never personally written a killall orca command only to have orca
> > > freeze. When that command is given, orca is killed by the kernel, and
> > > immediately. What I have noticed, and kyle backs this up in his bug
> > > report, is that once orca is started in lightdm's gtk greeter, all
> > > keyboard input never seems to reach lightdm. I can't figure out whether
> > > orca has frozen, or simply has nothing to speak. I seem to remember orca
> > > says "frame" once it is started and nothing more. You can no longer log
> > > in, kill orca, anything.
> > > Thanks
> > > Kendell clark
> > >
> > >
> > > On 12/02/2015 09:27 AM, Peter Vágner wrote:
> > > > Hello,
> > > >
> > > > As I have said the only thing problematic with lightdm vs orca usage is
> > > > the fact orca can't be killed gracefully. An ugly hack would be a script
> > > > which would trap sigterm and forcefully kill orca however I have started
> > > > this discussion so we can try to find someone who can give us some tips
> > > > on how to address it properly.
> > > >
> > > > If you don't care about starting at stopping orca on the login screen
> > > > i.e. sharing computer with sighted folks then you should be fine
> > > > tweaking it as I have explained at the bug here...
> > > > https://bugs.launchpad.net/lightdm-gtk-greeter/+bug/1483864
> > > >
> > > > Have you ever seen a case when you wrote killall orca and orca has
> > > > frozen? Can you reproduce it, then this is something I would like to
> > > > understand better.
> > > >
> > > > Greetings
> > > >
> > > > Peter
> > > >
> > > > On 02.12.2015 at 15:45 kendell clark wrote:
> > > > > hi
> > > > > THis has been going on for quite a while now. I've been following these
> > > > > bugs because they're causing some major issues in our  mate version of
> > > > > sonar. There's a catch 22. I can't include gdm because gdm pulls in
> > > > > lots
> > > > > of gnome, but lightdm causes issues with orca so I can't easily include
> > > > > that. But it's the only other accessible login dm. The best solution
> > > > > would be to use the unity greeter ubuntu and vinux use, but trying to
> > > > > build it in aur pulls in way too many ubuntu specific under the hood
> > > > > components, patched versions of gtk, unity libs, etc. Too much stuff to
> > > > > justify trying to get into community. I can't help you solve it but I
> > > > > wanted to publically encourage you to keep at it since the lightdm
> > > > > people seem to have written this off as too much effort, pick
> > > > > another dm?
> > > > > Thanks
> > > > > Kendell clark
> > > > >
> > > > >
> > > > > On 12/02/2015 05:15 AM, Peter Vágner wrote:
> > > > > > Hello,
> > > > > >
> > > > > > This is turning in to a little story, so please apologize for
> > > > > > posting a
> > > > > > lot of background details.
> > > > > > I am currently trying to run lightdm with lightdm GTK greeter
> > > > > > working on
> > > > > > my system. I would like to use it to either login into mate, or login
> > > > > > into xfce4 or login directly into kodi.
> > > > > > Lightdm appears to be only one accessible enough from the minimalist
> > > > > > desktop managers I know of.
> > > > > > Lightdm greeter started implementing accessibility support in a way so
> > > > > > it has preferences to launch on screen keyboard, screen reader from
> > > > > > its
> > > > > > menu. The problem with this initial goal was the issue where upon
> > > > > > dismissing the greeter session there was at-spi2 core bus still
> > > > > > present
> > > > > > and it was not easy to get accessibility support working inside the
> > > > > > resulting user session after logging in. Here is the corresponding bug
> > > > > > report https://bugs.launchpad.net/lightdm-gtk-greeter/+bug/1366534.
> > > > > > While in this state I was able to hack around the fact there are
> > > > > > lightdm
> > > > > > greeter processes open after the greeter is dismissed by using
> > > > > > session-setup-script and session-cleanup-script to kill these.
> > > > > > While not
> > > > > > particularly nice solution this worked pretty well.
> > > > > > There were issues with other stale processes so lightdm GTK greeter
> > > > > > now
> > > > > > implements a way to run some helper apps such as at-spi2-core or
> > > > > > applet
> > > > > > indicators specific processes remembers their pid's and gracefully
> > > > > > kills
> > > > > > these when exiting. While implementing this a feature that causes more
> > > > > > problem than it solves crept in unfortunately. Current versions of
> > > > > > lightdm GTK greeter now set NO_AT_BRIDGE environment variable. The
> > > > > > original reasoning behind this is that when lightdm greeter launches
> > > > > > at-spi2 it should force ATK not to launch it again by setting
> > > > > > ("NO_AT_BRIDGE", to true. The result of this is that orca is started,
> > > > > > at-spi2 is started but these can't communicate to each other I
> > > > > > guess. By
> > > > > > experimenting I have found out that orca and ATK won't start another
> > > > > > copy of at-spi2 core if one is already launched by lightdm so I think
> > > > > > this can be removed without risking other possible issues. The
> > > > > > corresponding bug report is at
> > > > > > https://bugs.launchpad.net/lightdm-gtk-greeter/+bug/1483864 .
> > > > > > So given this I hoped we might see awesome accessibility related
> > > > > > greeter
> > > > > > experience very soon but unfortunately I've found another issue and
> > > > > > this
> > > > > > time I am afraid it might have something to do with orca.
> > > > > > When lightdm GTK greeter is configured with reader in its
> > > > > > accessibility
> > > > > > states it includes Screen reader menu item which allows starting
> > > > > > orca. A
> > > > > > keyboard equivalent of enabling that menu item is an F4 keyboard
> > > > > > shortcut which is working as a toggle i.e. it switches screen
> > > > > > reader to
> > > > > > on or off. Under the hood lightdm GTK greeter launches orca or to be
> > > > > > precise the command configured in its config file, remembers its
> > > > > > pid and
> > > > > > then kills that pid when the feature is toggled to off.
> > > > > > What I have just noticed when orca receives sigterm it appears to
> > > > > > freeze
> > > > > > here. I am however only able to reproduce this when running inside a
> > > > > > lightdm greeter session and when logged into xfce for example I can
> > > > > > kill
> > > > > > orca without issues. This is with orca 3.18.2 and with orca master.
> > > > > > Unfortunately I can find nothing useful in the debug*.out file orca
> > > > > > generates. How would I go about trying to better troubleshoot this?
> > > > > >
> > > > > > I do have some other possibly related questions:
> > > > > > - Orca launches other helper apps such as speech-dispatcher which in
> > > > > > turn may optionally also launch pulseaudio. Should these also be
> > > > > > tracked
> > > > > > in lightdm GTK greeter the same way at-spi is?
> > > > > > - When lightdm is running as a systemd service and I call systemctl
> > > > > > stop
> > > > > > lightdm the greeter process is terminated however at-spi and I suspect
> > > > > > the other tracked processes are still running. Is this a bug?
> > > > > >
> > > > > > Greetings
> > > > > >
> > > > > > Peter
> > > > > >
> > > > > > _______________________________________________
> > > > > > orca-list mailing list
> > > > > > orca-list gnome org
> > > > > > https://mail.gnome.org/mailman/listinfo/orca-list
> > > > > > Orca wiki: https://wiki.gnome.org/Projects/Orca
> > > > > > Orca documentation: https://help.gnome.org/users/orca/stable/
> > > > > > GNOME Universal Access guide:
> > > > > > https://help.gnome.org/users/gnome-help/stable/a11y.html
> > > > > > Log bugs and feature requests at http://bugzilla.gnome.org