Re: fbcon + scrolling = irq timeouts?
Jakub Jelinek (jakub@redhat.com)
Tue, 30 Nov 1999 10:35:50 +0100
On Tue, Nov 30, 1999 at 10:21:31AM +0100, Gabor Lenart wrote:
> On Mon, Nov 29, 1999 at 10:57:55PM +0000, Alan Cox wrote:
> > > Has anyone else experienced IRQ timeouts while playing MP3s and scrolling
> > > large text files in a VESA framebuffer console? From what I can see, no
> > > cards are conflicting with each other in any way. Maybe someone else can
> > > help me out. Vital data:
> >
> > Welcome to VESA frame buffer. It uses BIOS functions. These can lock the
> > interrupts off for a long time. Basically no cure available
>
> VESA-2 compilant BIOSes introduced protected mode interface for video
> functions except (afaik) mode switching but it's needed only once.
> And if linear frame buffer is supported by your card, you have got the same
> memory mapped video ram area like with non-vesa frame buffer, isn't it ?
> I don't understand the differnece between vesa and non-vesa frame buffer and
> why do you lock interruppts ?
VESA BIOS is used for display panning if that feature has been enabled and
for that it is used on every scrolling.
But users can request video=vesa:redraw (I think it is the default) and no
BIOS will be involved after linear mode setup.
Cheers,
Jakub
___________________________________________________________________
Jakub Jelinek | jakub@redhat.com | http://sunsite.mff.cuni.cz/~jj
Linux version 2.3.18 on a sparc64 machine (1343.49 BogoMips)
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