[Intel-gfx] [PATCH 1/2] drm/i915: split PCI IDs out into i915_drm.h

[Chris Wilson]

On Thu, Jul 25, 2013 at 12:14:14AM +0200, Daniel Vetter wrote:
> On Wed, Jul 24, 2013 at 10:22:48AM -0700, Jesse Barnes wrote:
> > For use by userspace (at some point in the future) and other kernel code.
> > 
> > Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
> 
> Note that this split isn't too useful for userspace in newer generations.
> We still have the desktop/mobile split with since about ilk is meaningless
> for actual kernel code. Only recently with the haswell ult this changed
> again, but it's actually a different split. And userspace cares about gt1,
> gt2, ... for threads counts, which is not something too important in
> kernel land.

But things like SKU (mobile, desktop GT1, GT1++) are nicely encoded into
the PCI ID anyway (much to the horror of those who have to write the
matching tables), making for a much simpler test.

With the kernel's split, we can use the same listing in libdrm,
intel-gpu-tools and the ddx, at least. We've gone from maintaining 6
distinct copies to 3, which is some improvement at least. (And I think
the other 2 userspace copies could be converted.)

An alternative strategy that would work for at least the same set of
userspace is for the kernel to provide SKU details (desktop/mobile, gt,
etc) as a new ioctl... But for backwards compatability we would need to
maintain the huge PCI ID tables in userspace so the benefit is moot.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre