mieqProcessDeviceEvent make calls to mieqEnque with signals enabled - freezes Xorg server - multi-screen

[Donald Kayser]

Thanks for the quick response Jeremy. I was aware that I would miss  
events during this test, but that was better than freezing. I have not  
tried 1.10.x, but I will. We are trying to release a product soon and  
changing to a new server and distribution is not straightforward or  
the best move on our part. I might have to consider any other solution  
for the short term. I am glad to hear that we are not the only ones to  
have this problem and that it might already be solved. I will look  
further at 1.10.x and go from there.

Thanks again.
Donald


On May 17, 2011, at 4:49 PM, Jeremy Huddleston wrote:

> Ignoring SIGIO will just result in dropped events.  I seem to  
> vaguely recall that this issue was addressed at some point in the  
> past year or two since 1.7.x was active.  Have you tried 1.10.x or  
> master?
>
> On May 17, 2011, at 13:34, Donald Kayser wrote:
>
>> I am developing a system that include's the debian/squeeze  
>> distribution of xorg-server, version 1.7.7. I have come across a  
>> scenario where mouse movements on one screen and a touch on another  
>> screen will cause the Xorg process to freeze in an infinite loop in  
>> the function mieqProcessInputEvents(). I have traced the problem  
>> down to a small window during which a call to  
>> mieqProcessDeviceEvent can be interrupted by a signal and mess up  
>> the miEventQueue.head and tail. It appears that in some place in  
>> this stack a new event is being enqueued while the screen is  
>> changing and device messages get swapped to the wrong screen and  
>> back and forth.
>>
>> I put a global variable in mieqProcessDeviceEvent to indicate to  
>> mieqEnqueue to ignore data until finished. This has solved the  
>> problem as a test. I am now writing the code to ignore the SIGIO  
>> signal during mieqProcessDeviceEvent and test this approach also.
>>
>> Does anyone have a similar problem or advice?
>>
>> Thanks
>> Donald Kayser
>> xorg at kayser dot net
>>
>>
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