On Tue, Dec 06, 2011 at 12:21:02PM -0800, Jesse Barnes wrote: > On Tue, 06 Dec 2011 11:56:07 -0800 > Eric Anholt <eric at anholt.net> wrote: > > > It's one of those "been there forever" bits. A comment wouldn't hurt, > > > but we should also put in a doc change request (in fact I think I did > > > that but it went into a black hole). > > > > Well, by "been there forever", you mean "introduced in: > > > > commit a69ffdbfcba8eabf2ca9d384b578e6f28b339c61 > > Author: Zhenyu Wang <zhenyuw at linux.intel.com> > > Date: Mon Aug 30 16:12:42 2010 +0800 > > > > drm/i915: Enable MI_FLUSH on Sandybridge > > > > MI_FLUSH is being deprecated, but still available on Sandybridge. > > Make sure it's enabled as userspace still uses MI_FLUSH. > > > > Signed-off-by: Zhenyu Wang <zhenyuw at linux.intel.com> > > Cc: stable at kernel.org > > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>" > > > > It should be removed on Ironlake, and fixed to be 12 on SNB or just > > removed. > > No, "fixed to be 12" would just encourage people to still try it and > break their machines. We can safely remove it now that we don't use it > anywhere. And we can fix the docs so that if people do want to mess > with it they won't try bit 12. If userspace ever relied on this being enabled we cannot just disable it now - it would break the kernel<->userspace abi on snb. You have to wait for 5-10 years, eternity or until the last userspace using this disappeared, whichever comes first ;-) Cheers, Daniel -- Daniel Vetter Mail: daniel at ffwll.ch Mobile: +41 (0)79 365 57 48
