hybrid-graphics-linux team mailing list archive

[Dave Airlie <airlied@xxxxxxxxx>]

On Wed, Jul 14, 2010 at 4:42 AM, Ruslan N. Marchenko <ruff@xxxxxxxxxxx> wrote:
> On Tue, 13 Jul 2010, Dave Airlie wrote:
>>
>> As for fglrx you might be able to extract the BIOS and shove it into
>> 0xc000 location where fglrx will most likely look for it, though I'm
>> not sure how best to do that.
>>
>
> BTW, who is doing that bios remapping during card switch? I just dumped
> memory with dd from 0xc0000 and it is intel vga bios. Switched to radeon -
> but memory dump shows the same intel bios.
>

With switcheroo, its really a complete stack thing that makes the magic work.

Since userspace doesn't need the BIOS ROM with KMS drivers we don't
need to do anything seriously different,
we change a couple of flags around in the resource code to make X
believe the primary GPU has changed, but
if X needs the ROM it also tries to get it via libpciaccess which is
smart enough to do the right thing.

I suspect for fglrx extracting the ROM, and trying to overwrite the
one at 0xc0000 might actually work.

As for the crazy stack in radeon kms driver, there are lot of places
the ROM can be found, and we just fallback in order depending on the
type and state of the GPU, i.e. IGPs use one path, unposted GPUs
another etc.

Dave.