vga arbiter (news)
vignatti at c3sl.ufpr.br
Fri Nov 23 06:51:00 PST 2007
Alan Cox escreveu:
>>  http://people.freedesktop.org/~vignatti/VGA.Notes
> This seems to imply that there is a single locked instance of the VGA
> legacy addressing. That isn't neccessarily the case. On some PA-RISC for
> example you have multiple PCI busses hanging off the system busses.
> So the arbiter needs to know about PCI. Your kernel interface seems to
> but not your X one ?
yes, the architecture can set a hook to override enabling/disabling of a
given device resources in the kernel. With the current userspace
implementation (libvga) this is hide for the clients. So yes, the X
doesn't know anything about this right now. It should?
> A second question this leads onto is basically about the interface. I
> would expect a sysfs interface to have made more sense with one node per
> candidate vga device.
This can be easily implemented. "Only" a massive modification on the
userspace side :( But what would be the practical benefit of the sysfs
interface that a char device doesn't has here?
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