[haiku-development] Re: S3 Video Driver

Gerald Zajac <zajacg@xxxxxxxxxxxxx> wrote:
> Axel Dörfler wrote:
> > Gerald Zajac <zajacg@xxxxxxxxxxxxx> wrote:
> >> The plain Trio64 86C764 is not supported because it does not
> > > support
> >> Memory Mapped I/O (MMIO).  If someone has any ideas about how to
> >> handle,
> >> under BeOS/Haiku, a video chip that supports only PIO, I might
> >> consider
> >> supporting that chip.  The Trio64V+ 86C765 does appear to support
> >> MMIO,
> > The only way you can do this is to either move some of the
> > functionality into the kernel module, or you make port out/in
> > available
> > to the accelerant (through an extra ioctl()).
> Since the accelerant has to access a number of registers, I feel that
> it
> would be rather cumbersome and time consuming to access the registers
> via the kernel module;  thus, IMHO it is best not to support the
> plain
> Trio64 chip.

The PIO mode is a performance problem in itself - using a syscall per
port access isn't that problematic; and you could always turn off
acceleration if it really would be a problem. Being able to change the
resolution would be a good start, though, I think.
But it's your decision, anyway! :-)

Bye,
   Axel.

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