Re: [Patch, RFC] Make struct fb_info ref-counted with kref

[Guennadi Liakhovetski <g.liakhovetski@gmx.de>]

On Mon, 20 Sep 2010, Bruno Prémont wrote:

> On Mon, 20 September 2010 Guennadi Liakhovetski wrote:
> 
> > 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
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/