VRAM detection in controlfb.c

Daniel Jacobowitz drow at false.org
Fri Apr 28 14:07:45 EST 2000

On Thu, Apr 27, 2000 at 11:39:59PM -0400, Clint Hepner wrote:
> I recently added another 2MB of VRAM to my PM8500
> with control video, and was dismayed when linux wouldn't
> recognize it.  I remembered some discussion on this
> issue about a month ago, but I haven't seen anything
> since then.
> I got the most recent version of the stable kernel,
> 2.2.15_pre20, and poked around a bit to try to understand
> what was going on.  In the end, I just hardcoded the value
> of bank2 after line 725 in controlfb.c to 1, to
> override the kernel's failure to detect the memory
> in bank 2. It worked; I can now drive my 17" monitor at
> 1280x1024 @16bpp.
> My question is, is the problem only with detecting the
> VRAM, or could there be problems addressing the VRAM as
> well if the kernel isn't able to detect it on its own.

No, there shouldn't be any problems.

Two things:  pre20 from Linus or from Cort's tree or from one of the
others?  Also, could I persuade you to see if 2.3 detects the memory

I may just support a boot parameter for this if I can't figure it

> (On a slightly unrelated issue, is control capable of
> resolutions greater than 1280x1024? I've never seen
> any documentation on it.  MacOS doesn't give me the option
> of going higher, but I'm not sure if that means anything.)

I doubt it.  If it is, Linux doesn't know how.


/--------------------------------\  /--------------------------------\
|       Daniel Jacobowitz        |__|        SCS Class of 2002       |
|   Debian GNU/Linux Developer    __    Carnegie Mellon University   |
|         dan at debian.org         |  |       dmj+ at andrew.cmu.edu      |
\--------------------------------/  \--------------------------------/

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