[coreboot] how to prevent legacy resource conflictwith multiple VGA cards

Carl-Daniel Hailfinger c-d.hailfinger.devel.2006 at gmx.net
Sun Oct 31 02:40:04 CEST 2010

On 30.10.2010 07:07, Scott Duplichan wrote:
> Whew, finally solved this problem. 1600 x 1200 32-bit color is now working
> with the Win7 in-box ATI driver. The problem is that some important
> information is passed from coreboot to the ATI video driver, and some of
> it was incorrect. The information is passed by placing it in the last
> 512 bytes of the frame buffer, so it is easy to look at. The format of
> the information is in struct ATOM_INTEGRATED_SYSTEM_INFO_V2.
> I should have thought of this when the slow HT link problem resulted in
> screen tearing. The driver tries to never let this happen. One of the
> items passed to the driver is HT link frequency and width. Hard-coded
> values were used for link frequency and width, and frequency was invalid.
> Apparently the driver skipped the bandwidth checks because of this.
> I believe with this change, Win7 will be able to get through setup
> smoothly and most everything will be working. There are several more
> patches to submit before mahogany_fam10 will have all of the Win7 changes.

Awesome detective work, Scott!

If you ever have the time, please write down all the stuff you had to go
through to find and fix the bugs you encountered, or at least talk about
it and record it with your MP3 player so someone else can transcribe it.
Transcribing may be a task suitable for Google Code-in 2010 because it
adds documentation about the project.



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