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[directfb-users] Re: WAITFORSYNC sleeps too long
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[directfb-users] Re: WAITFORSYNC sleeps too long

Hi Ville,

first of all thank you for your quick and comprehensive reply. :)
I'm forwarding this to my colleagues so hopefully we'll see clearer by

> > Why does the wait_event_bla fail? Isn't there any VSYNC interrupt? How
> > can this happen? 
> Obviously the first thing to check is if your kernel actually supports 

Are there any 2.6 kernels that don't support it? How can we check this?
Probably by looking at the sources?

> Secondly make sure the graphics card actually has an irq assigned to it. 
> BIOS usually has an option for it. lspci should tell you if the irq is 
> assigned.
> If everything checks out the next step would probably adding some debug 
> printks to the kernel to see what happens. One thing that might be the 
> cause is some irq routing problem (ACPI related maybe).

That means switching ACPI off could help?

> > I've got no idea of where this interrupt should normally come from, but
> > could this be caused by a second PCI graphics board in the machine, on
> > which an Xserver runs?
> I doubt that should cause any problems unless the Xserver is told 
> to touch the G550. Or maybe the Xserver is stupid an pokes at some 
> VGA ports while shouldn't. Which card is inited by the BIOS?

I guess it's the PCI card, but I'll check this.

> If someone actually disables the interrupt you should see a message from 
> matroxfb with dmesg.

ok, we'll see.


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