GNOME Bugzilla – Bug 409055
Terminal stays blank
Last modified: 2007-03-15 18:47:44 UTC
Please describe the problem: When switching workspaces, the gnome-terminal screen sometimes stays blank. See ubuntu bugreport: 85437 for a screenshot https://launchpad.net/ubuntu/+source/gnome-terminal/+bug/85437 This is amd64. Steps to reproduce: 1. open terminal 2. switch workspace 3. switch back, look at terminal, sometimes it stays blank Actual results: Expected results: Does this happen every time? No Other information:
According to the launchpad bug, this is 2.17.91-0ubuntu1. Chris, I've seen this too once on a non 64bit x86, using vte's vte. Only it did not stay blank, but just was not repainted. I have not been able to do it since.
I need a few more hints on how to reproduce this... The prime suspect is a mishandling of a visibility notify, but going over that path everything looks sane... Except we never receive (Edgy) a fully-obscured notify when leaving the workspace so it should just be a normal expose event. * perplexed.
What can I do to debug this? I've looked into the debug flags but I haven't gotten very far.
Miek, if you can reliably reproduce this, then I think the debug output for VTE_DEBUG_FLAGS=events,updates should help. Also, I've added some more debugging output to HEAD, so if you could try running from svn it might help even more. Thanks.
Ok, I've applied a patch to ensure we set the fully-obscured flag when the user switches workspaces. Unfortunately, I think this will only hide whatever bug you have managed to trigger here. However, please try HEAD and see if you can find any aberrant behaviour. r1698: 2007-02-19 Chris Wilson <chris@chris-wilson.co.uk> As noticed on bug 409055, we do not receive a visibility-notify event when we switch workspaces (or even when the window is iconified). The workaround for this is to watch for our toplevel being unmapped and set the fully-obscured flag. * src/vte.c: (vte_terminal_configure_toplevel), (vte_terminal_unmap_toplevel), (vte_terminal_hierarchy_changed), (vte_terminal_set_visibility), (vte_terminal_visibility_notify):
Cannot get any output with VTE_DEBUG_FLAG. but running from: Path: . URL: http://svn.gnome.org/svn/gnome-terminal/trunk Repository Root: http://svn.gnome.org/svn/gnome-terminal Repository UUID: e32f9464-e525-0410-8908-8a3b6990da27 Revision: 2171 seems to fix the issue. Running ./src/gnome-terminal and a "normal" one shows that the normal one is blank after a workspace switch and the one from trunk is not. thanks!
Miek, did you install a new vte too? (Also, keep in mind that if you run ./src/gnome-terminal while there is already another one running (from ./src or not) then you'll not get a window from ./src but from the already running one. When doing tests, it's always safer to run ./src/gnome-terminal --disable-factory to be sure that one is testing the correct binary.)
./src/gnome-terminal --disable-factory gives the same result (i.e: that works), "normal" gnome-terminals still blank. Before I just started gnome-terminal from an xterm. Haven't installed any new libvte. I can thus confirm that the patch seems work.
Miek, the patch Chris committed was to vte, not gnome-terminal. If you only built gnome-terminal from trunk, and not vte,then you are not testing the patch ;-)
Ah, that explains why I still the bug... :P Retrying with a new vte.
ok, rebuild vte from svn/trunk. I've build debian packages from those sources by copying the debian/ directory from ubuntu into it. Running with those installed I still get blank terminals... although less often. Some observations: Scrolling in Epiphany helps in getting the bug :P The terminal size also seems to have an effect. I start my gnome-terminals like this: /usr/bin/gnome-terminal --geometry 100x60 $@ "normal" started terminals (which are smaller) are not as much affected. Also, with the new vte, it seems like only one terminal can be affected at the time, unlike previously where all my terminal windows were blanked. The terminal which "has" the mouse in it, is affected, the other one is not: 1. switch the other workspace 2. move mouse the right 3. switch back 4. terminal with the mouse in it is blank If I move to the left, the other one is blank, but not always.
By maximising the terminal, I reproduced this first time. Thanks.
Hmm, the root cause of this seems to be a reordering of the visibility+expose events:- Order reported by xev: MapNotify event, serial 13, synthetic NO, window 0x4e0000f, event 0x4e0000f, window 0x4e0000f, override NO VisibilityNotify event, serial 13, synthetic NO, window 0x4e0000f, state VisibilityPartiallyObscured Expose event, serial 13, synthetic NO, window 0x4e0000f, (0,0), width 1537, height 2, count 2 Expose event, serial 13, synthetic NO, window 0x4e0000f, (1706,0), width 214, height 2, count 1 Expose event, serial 13, synthetic NO, window 0x4e0000f, (0,2), width 1920, height 1150, count 0 Output from gtk+ debug=events: Gdk-Message: map notify: window: 85983247 Gdk-Message: expose: window: 85983247 2 x,y: 0 0 w,h: 1547 2 Gdk-Message: expose: window: 85983247 1 x,y: 1716 0 w,h: 204 2 Gdk-Message: expose: window: 85983247 0 x,y: 0 2 w,h: 1920 1150 Gdk-Message: property notify: window: 85983247, atom(245): "WM_STATE" Top level parent mapped. Expose (0,0)x(1920,1152) Gdk-Message: map notify: window: 85983286 Gdk-Message: visibility notify: window: 85983286 partial Gdk-Message: expose: window: 85983286 2 x,y: 0 0 w,h: 1547 2 Gdk-Message: expose: window: 85983286 1 x,y: 1716 0 w,h: 204 2 Gdk-Message: expose: window: 85983286 0 x,y: 0 2 w,h: 1920 1150 Gdk-Message: property notify: window: 85983247, atom(231): "_NET_WM_STATE" Gdk-Message: focus in: window: 85983247, detail: NotifyNonlinear, mode: NotifyNormal Gdk-Message: client message: window: 85983247 Gdk-Message: expose: window: 85983286 0 x,y: 1714 0 w,h: 2 2 Gdk-Message: property notify: window: 310, atom(288): "_NET_CLIENT_LIST" Gdk-Message: property notify: window: 310, atom(289): "_NET_CLIENT_LIST_STACKING" Gdk-Message: property notify: window: 310, atom(294): "_NET_ACTIVE_WINDOW" Gdk-Message: property notify: window: 310, atom(294): "_NET_ACTIVE_WINDOW" Visibility (fully-obscured -> partial). Order as processed by vte: Top level parent mapped. Expose (0,0)x(1920,1152) vte_terminal_paint (0,0)x(1920,1152) pixels vte_terminal_paint_area (0,0)x(1920,1152) pixels, (0,0)x(319,88) cells [(0,0)x(1914,1144) pixels] Visibility (fully-obscured -> partial). Which basically means that the exposes on the second window (which maps to the same GdkWindow as the first) are amalgamated into a single GdkExposeEvent and processed *before* the visibility notify - which we use to decide if the expose event actually needs to be processed or not.
r1705: 2007-02-19 Chris Wilson <chris@chris-wilson.co.uk> Bug 409055 – Terminal stays blank Due to GTK+ coallescing of XExposeEvents it was possible for our GdkExposeEvent to arrive before the GdkVisibilityEvent associated with the mapping of our toplevel and so we discarded the event as we believed we were still unviewable. * src/vte.c: (_vte_invalidate_cells), (vte_terminal_expose), (reset_update_regions): Assume that all GdkExposeEvents have been checked for suitability before delivery. We know this true for locally generated expose events which are extensively checked during invalidation, and we presume that X will not generate expose events on unmapped or otherwise unviewable windows.
This bug is back with gnome 2.18.