[coreboot] [PATCH] Fix AMD HD 3200 uma graphics problems in Win7 (revised)

[Carl-Daniel Hailfinger]

Hi Scott,

I am not totally convinced that all changes are a net win.

On 03.11.2010 05:29, Scott Duplichan wrote:
> (Re-submitting with correction to GFX debug bar setup procedure needed
> for use with AMD family 0Fh processor).
>
> This patch solves crashes and BSODs that occur when booting Win7 with
> AMD RS780 uma graphics. Tested with frame buffer sizes 64m through 1GB
> by running dxdiag and Windows media player at 1600x1200 true color.
> Additional changes needed to boot Win7 on Mahogany_fam10 will follow.
>
> -- Enable and program the debug bar as required by the ATI graphics driver.
>    First, make the debug bar writable and allow resource allocation code
>    to program it. Once programmed, enable its operation.
>   

Good.


> -- Disable the family 10h processor mmconf while the RS780 mmconf is in use.
>   

I thought the family 10h processors need their own MMCONF for some
configuration accesses. If this disable happens after all such config
writes are done, I'm OK with it.


> -- Make strap programming more closely follow the reference BIOS.
>   

Good.


> -- Disable PCIe bar 3 after using it.
>   

This one is something I have reservations about. Isn't PCIe BAR 3 the
one via which MMCONF accesses are done? How is MMCONF going to work
after that?


> -- UMA size is no longer hardcoded.
>   

Nice.


> -- Disable write combining for all steppings to eliminate stability problem.
>   

This may have a performance impact, right? Do you know if any steppings
with stable write combining exist?


> -- Correct task file data.
> -- Improve the accuracy of the Atom table that passes information to the driver.
>   

Yes, that's definitely needed.


> Signed-off-by: Scott Duplichan <scott at notabs.org>
>   

I think the patch looks good, but I'd like a few answers before I ack it.

Regards,
Carl-Daniel

-- 
http://www.hailfinger.org/