[coreboot] Geode LX VGA BIOS Patch
Chris Kindt
chriskindt at umbc.edu
Tue Aug 25 20:54:48 CEST 2009
Another Updated Patch:
So far I have heard of problems when using a lcd connected to the
vga port and when switching from X to back to the console. I was able to
replicate problems and address them with this patch.
For the lcd issues, the left side of the screen was distorted and
cropped. This was a timing problem from using incorrect modes. My crt
was able to function correctly with these modes. There were two issues
with the mode table. When creating the patch I copied the original
seabios table instead of the geodelx modified table. Then even with the
correct geodelx table, the seabios table is still addressed at compile
time. The geodelx-v3 patch includes the modified table, while the
geodelx-modehack patch is a temporary quick fix to address the right table.
For switching from X to the console, the display controller
registers need to be reset to enable vga . These are DC_GENERAL_CFG=0x80
and DC_DISPLAY_CFG=0x48. The linux vgacon vt driver only saves the
standard vga io ports and memory. I am looking into doing this with vesa
extensions from X. For now an easy way to do this is to re-post the
vgabios with vbetool or svgalib. I removed exiting if legacy io checking
fails so reposting is possible.
seabios-geodelx-v3.patch
-replaced video parameter table
-removed quiting when legacy io fails
-fixed spelling
seabios-geodelx-modehack.patch
-temporary fix to use correct video timing
Chris Kindt
Signed-off-by: Chris Kindt <chriskindt at umbc.edu>
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