Dear Andreas
Thank you very much for coming up already with a solution to your problem. I would not be surprised that this portion of code is buggy, because querying hasPendingEvents() inside a thread is already a weird way to decide to drop an event. Your patch looks simple but would need to be reviewed by somebody with some experience with threading in Qt applications to be sure it does not risk making things weirder. (I have some project to revisit this code for 2.3.0 because it looks like a fun thing to learn, but now is not really the moment for me...) In case your patch does not make it in time for 2.2 (because as far as I understand the next step is a release candidate), can we try to see where your issue comes from? I am thinking about the fact that there already were issues of input methods interfering (here IBus: <http://www.lyx.org/trac/ticket/9362>). Your bug is certainly not #9362 though because one of its symptoms is that the message "system is busy" is not displayed (and the event not dropped). I wonder whether it could be something else. For this reason could you please try to see if you can reproduce your issue when you run LyX with the following command line? XMODIFIERS= lyx Also, since you suspect that interfering events might be coming from timers: do you have the source view open when the bug occurs? I am sceptical that the age of your laptop is the (sole) issue here, because when I use valgrind to profile LyX, it also goes very slowly, and I have never experienced issues of this sort (unless I had IBus running). Sincerely Guillaume Le 07/03/2016 01:13, Andreas Amann a écrit :
Hi, when I use lyx-2.1.4 on an older laptop (Celeron 550, arch-linux) I cannot use the cursor left and right keys in the usual way. They get stuck after moving by just one character, even if I keep the key pressed, and then I get a staggered irregular cursor motion. The problem is also present on the current master branch. (Interestingly I do not see this issue with a faster computer with otherwise similar setup). when starting lyx with lyx -dbg key error messages of the form GuiWorkArea.cpp (1053): system is busy: scroll key event ignored appear. The reason seems to be that there are other unrelated events pending in the Qt eventloop (possibly timer events for cursor blinking?). This causes lyx to drop the cursor motion events. The attached patch against the current master branch fixes the problem for me. It first processes all events which are not caused by user input, and only if this does not clear the event queue proceeds to drop the current event. Would you consider applying this to master (and possibly backport to 2.1.x)? Thanks, Andreas
