-------------- Original message ---------------------- From: "Daniel
Rozsnyó" <[EMAIL PROTECTED]>
Patrick McNamara wrote:
Timothy Miller wrote:
On 7/26/06, Richard Smith <[EMAIL PROTECTED]> wrote:
As a linuxbios developer I'm nervious enough as is about with
all this talk about making the RAM controller setup and
Video modes "Software" problems.
No memory or video controllers are going to be running right on
reset. The only difference for us is that they're more complex
to program. Although Patrick's perl stuff is very complex, a
simple piece of C/asm code that converts timing numbers
directly to a video program would be very small.
Specifically it is 1667 bytes to generate the appropriate video
controller binary image with arbitrary timing values. That is
when compiled with the stock gcc 3.4.5 optimizations.
If the video-bios does support only the VGA modes (13 or how much
they are in the standard) then one can pre-generate the video
controller binary & store diffs for various modes. This might be
less, than a mode table + algoritm to generate the binary in
runtime.
[EMAIL PROTECTED] wrote:
Be careful about painting yourself into a corner. OGD1 logic testing
can begin with a limited set of VGA modes, but the final OGA1 design
in TRV10/OGC1 will need to come to grips with providing a capability
to power-up running any arbitrary video mode -- because some
monitors won't work any other way. And remember, part of the TRV10
application space is embedded systems. Cthulhu only knows what
display systems it might have to drive. Don't assume VESA mode
compatibility.
I think that it is the other way around. PC MotherBoards are going to
request a VGA mode that needs to be supported. This VGA mode is only
used until the OS loads a graphics driver. Linux uses VGA/VESA for text
mode console so that is going to be needed unless we have a Kernel
driver for console mode.
OTOH, an embedded system that didn't boot with a VGA mode is going to
need to contain the code needed to load the driver to start up the
graphics card. Such systems probably wouldn't even have a VGA/VESA
Video BIOS.
--
JRT
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