[Openchrome-devel] Early TTM patch

Xavier Bachelot xavier
Fri Jan 21 05:46:57 PST 2011

On 01/17/2011 09:18 PM, James Simmons wrote:
> Okay folks brace yourselves. I managed to hook the current DRM kernel apis 
> with a TTM/GEM backend. The UMS xorg servers appears to run fine. Now it 
> is far from perfect. Currently you can't unload the module without a 
> oops but so far that is the only problem I have seen. But other than that 
> it runs!!! Since I don't have a freedesktop account yet I posted my patch 
> at 
> http://www.infradead.org/~jsimmons/via-ttm.diff
> This patch is against the drm-next branch. Give it a try with the KMS xorg 
> branch and let me know how it works. While you test that I'm going to put 
> some gem test together to exercise the driver.
The VRAM probing for the KM400/KM400A/P4M800 (chipset id 0x7205) will
fail when on the P4M800 variant because it's using a different host
bridge and then the VRAM needs to be read from another register. The
chipset to host bridge mapping seems to be 1:1 in all but this case.
The VRAM probing is broken in this case too for UMS, but it might worths
fixing it right from the start for KMS.
There's a bug filed for this issue :

for a host bridge probing implementation.


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