Re: git pull] drm for v4.1-rc1

Matthew Garrett
2015-04-23T22:59:54Z

On Thu, Apr 23, 2015 at 3:47 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:

> I'm not sure why we want that IORESOURCE_ROM_SHADOW thing at all, but
> yes, if what this is all about is the magic video ROM at 0xc0000, then

It's used in the PCI layer to say "Read from 0xc0000 rather than the
ROM BAR" and then ends up as a shorthand for "Was this the boot video
device" in various places because we're bad at software.

> There is no way to see that from the PCI device state, because as
> mentioned, quite often the "ROM" is entirely fake, and is not just
> some shadowed copy of a real underlying hardware ROM, but is
> fundamentally just a RAM image decompressed from some other source and
> then marked read-only.

If only - nvidias used to rewrite their image at runtime.

--
Matthew Garrett | matthew.garrett@coreos.com