> > Svgalib's kernel module has an ioctl that waits for retrace, using 
> > the
> > card's interrupt. This functionality of the module is independent of
> > svgalib, and can be used also in X11, text mode or fbdev.
> 
> Similar for the DRM ioctl, but it requires a privileged client like
> the X server to enable the interrupt. How is that handled by the
> svgalib kernel module? Also, I suspect that the svgalib module
> relies on a BIOS whereas the DRM has no such dependencies.

There is no dependency on the bios. There is card specific code for some
cards, and generic VGA code that is supposed to work on all cards (but
does not).
Access control is by the permissions on the device node. In the current
module using this node gives access to all the card's Memory and IO, but
sync interrupt can be seperated to a different device. The interrupt is
enabled only when the ioctl is issued, and disabled after it occurs
once.



-- 
Matan Ziv-Av.                         [EMAIL PROTECTED]


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