On Mon, 20 Sep 2010, Bruno Prémont wrote:

On Mon, 20 September 2010 Guennadi Liakhovetski wrote:

quoted

Of course, the optimal solution would be to design and implement a
mechanism to notify framebuffer users about a changed fb configuration,
but we're not that far yet...

This would include ABI change for userspace, hard to get it trough...
(except maybe if userspace has to opt-in for the notification and kernel
can thus differentiate the "old" and "new" users)

Yes, something like that...

But how would you handle userspace apps that can't consume notifications right
away? Do you timeout or risk long stalls?

In the same way as they're currently [1] handled: as long as there are 
active fb-users, I reconfigure the physical interface but preserve the 
user configuration, i.e., I either display the smaller user framebuffer on 
a part of the larger display or a part of the larger user framebuffer on 
the whole smaller display.

[1] http://thread.gmane.org/gmane.linux.ports.sh.devel/8751

Thanks
Guennadi
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Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/