epia800 direct vga working

Steve Gehlbach steve at nexpath.com
Sun Sep 21 13:27:00 CEST 2003


SONE Takeshi wrote:
> On Sat, Sep 20, 2003 at 11:25:58PM -0700, Steve Gehlbach wrote:
> 
>>Nathanael Noblet wrote:
>>
>>
>>>I don't need a framebuffer on boot, but once loaded would I be able to 
>>>insmod the epiafb module and get that working? 
>>
>>More than likely, since a framebuffer driver made for epia vga must have 
>>intimate knowledge of the chipset, so it should completely initialize it.
> 
> 
> Unfortunately it does not. Looks like we have to program some more
> VGA registers for framebuffer to function properly.
> 
> 

Hmmm... this is strange.  Has anyone used HAVE_FRAMEBUFFER option 
without VIDEO_CONSOLE and gotten that to work?  The only difference is 
the 0xFB chipset register, however, the setting I use matches the Award 
setting when it boots.  The HAVE_FRAMEBUFER sets the framebuffer size to 
something different, but I don't think this is releveant, my setting 
would be 8M but the frambuffer access bit (bit 3) is off, and the 
address of the framebuffer is not set (bits 2-0 and reg 0xFA and others).

I suspect it has something to do with the graphics aperture settings 
(GA).  The GA relevant registers are 0x13 and 0x80-0x8B.  You can try 
putting in the settings at the bottom of afteram.inc (this file is not 
used in my config), the CS_WRITE commands to 0x13, 0x84, 0x80, 0x88. 
These match the Award settings, except for 0x84, which is 0 in Award 
(256M aperture) rather than 0xc0 (64M aperture). I know that these 
registers can cause hangs, though. I would try putting these in the 
vgainit.inc file replacing the 0x88 setting where it says "turn off GA".

Which epiafb are you using?  Maybe I can try it later this week, but I 
am not a big user of framebuffers.

-Steve





More information about the coreboot mailing list