Radeon : Exclude some memory zone

[Dave Airlie]

2010/1/11 Jerome Glisse <glisse at freedesktop.org>:
> On Sun, Jan 10, 2010 at 07:06:41PM +0100, José JORGE wrote:
>> A Segunda 04 Janeiro 2010 23:46:32 José JORGE você escreveu:
>> > The question : is it possible by myself to change the radeon driver to
>> >  ignore a memory zone of a video card? Something like the badram patch for
>> >  linux kernel?
>> Just if someone had the time to answer simply forget it, or maybe done with
>> lots of work, I'd thank him...
>
> It's doable, i think best way would be to allocate a serie of BO
> covering the damaged area using the new ttm allocator which allow
> to specify addr of BO. Then you need to pin all those BO. Maybe
> the trickier part is to design the commandline argument to allow
> such thing.

Most GPU memory is interleaved so if one chip is broken you can't just
ignore it linearly, its probably possible to reconfigure the memory controller
but I can't imaging a 256-bit memory bus working at 192-bit so well,
and you'd lose more than one RAM chip.

Dave.