Re: [PATCH] DRM / i915: Fix resume regression on MSI Wind U100 w/o KMS

[Dave Airlie <airlied@gmail.com>]

On Tue, Jan 12, 2010 at 2:38 AM, Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
> On Sun, 10 Jan 2010 07:32:30 +1000
> Dave Airlie <airlied@gmail.com> wrote:
>> I'm in the 2-3 years at a minimum, with at least one kernel with no
>> serious regressions in Intel KMS, which we haven't gotten close to
>> yet. I'm not even sure the Intel guys are taking stable seriously
>> enough yet. So far I don't think there is one kernel release (even
>> stable) that works on all Intel chipsets without
>> backporting patches. 2.6.32 needs the changes to remove the messed up
>> render clock hacks which should really have been reverted a lot
>> earlier since we had a lot of regression reports. The number of users
>> using powersave=0 to get anything approaching useable is growing etc.
>
> But you could apply that argument to the existing DRM code (not just
> Intel) as well; lots of things are broken or unimplemented and never
> get fixed.  I'd say the right metric isn't whether regressions are
> introduced (usually due to new features) but whether the driver is
> better than the old userspace code.  For Intel at least, I think we're
> already there.  The quality of the kernel driver is higher and it has
> many more features than the userspace implementation ever did.  That's
> just my subjective opinion, but I've done a *lot* of work on our bugs
> both in userspace and in the kernel, so I think it's an accurate
> statement.

The problem is at any single point in time I'm not sure a kms kernel
exists that works across all the Intel hw, which from a distro POV is a real
pain in the ass, a regression gets fixed on one piece of hw just as
another on a different piece gets introduced.

I'd really like if Intel devs could either slow it down and do more testing
before pushing to Linus, or be a lot quicker with the reverts when stuff
is identified. The main thing is the render reclocking lately, thats been a
nightmare and as far as I can see 2.6.32.3 still has all the issues,

>
> It doesn't have to happen anytime soon, I was just thinking that
> removing the old, pre-KMS code would make it easier to avoid
> introducing regressions since we'd have one less config (a bit one
> atthat) to worry about.

Maybe in 3-4 years.

Dave.