Re: [Qemu-devel] Re: RFC for new features

[Derek Fawcus <dfawcus@cisco.com>]

On Fri, Jul 09, 2004 at 11:13:30PM +0100, Antony T Curtis wrote:
> > 2) There are device emulation issues :
> > 	The current cirrusvga is a vast improvement over the previous bochs 
> > device. However, pushing available memory to more than 4 Mb wold allow for 
> > better resolutions : 1024x768x16 is a bit limiting in some uses.

Huh - I don't think there are any specific pitch restrictions on this chipset.

4M should allow 1280x1024@24bpp (or 1152x864@32bpp).  Is that not enougth?

> Well - the CL-GD544X chips can only handle 4MB of memory, maximum. For
> larger framebuffers, we would have to emulate a different video chip -
> If we wish to stick to Cirrus Logic, The Laguna CL-GD546x chips can
> address up to 16MB I think....

Nope.  Only 8M.  The architecture has scope for 2 RAMBUS channels,  but they
only implemented chips with 1 RAMBUS channel.  One of the fields in the
channel control register is 3 bits,  identifying the number of 1M ram banks
available...  (Someone who has spent too long playing with Laguna chips).

Besides,  the Laguna is a more complex beast with a 3 operand BitBLT engine...

DF