[coreboot] how to prevent legacy resource conflict with multiple VGA cards

Myles Watson mylesgw at gmail.com
Thu Oct 28 18:25:51 CEST 2010

> I found and tried CONFIG_CONSOLE_VGA_MULTI. I see a couple of problems
> with it. First, it seems to apply only to AMD K8 and family 10h processors
> (in my case this is OK). A bigger problem is that it seems to control
> VGA on an HT link by HT link basis. One problem there is that an HT link
> could have multiple graphics cards. The CONFIG_CONSOLE_VGA_MULTI doesn't
> work for me for a different reason. The graphics that needs to be disabled
> is not on an HT link at all, it is the internal UMA graphics.

Internal to where?  Is it internal to the processor?

I think in the past it has been enough to set the VGA bits on the bridges.
I guess there could have been a problem where there were two VGA devices on
the same bus.

So you want to implement the logic to disable UMA if there's an external VGA
device added, right?  It seems like the place to add that is in the code for
the device that implements it.  Do you want to disable allocation of the UMA
area if there's an external card too?


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