Linux Plumbers Android+Graphics microconf summary

[Daniel Vetter]

On Thu, Oct 10, 2013 at 01:07:58PM -0700, John Stultz wrote:
> ADF:
> 
> * Rob has reposted his atomic modesetting patches, which helps adress
> part of some of the issues Greg tried to resolve with ADF, although
> there still is the delta vs full update issue.
>     http://www.spinics.net/lists/dri-devel/msg46413.html

I've read up your excellent lwn write-up and tbh I don't understand why
this is an issue - userspace can always opt to emit the full state if it
wants to. And drm already keeps all the properties around somewhere (afaik
at least) so I don't think drivers have to keep track of that much stuff.

So a simple "just write the entire hw state" model should be doable with
not that much work.

> * The need for KMS helpers to reudce boilerplate seemed to be widely
> agreed upon, but I'm not sure if anyone is actually planning to put any
> effort.

Imo this is simply ongoing stuff done on a as-needed basis. Personally I
have some plans to extract more helpers for handling the dp aux
transactions and sink detection.

I have a bit the impression that part of this due to the helper code in
drm_crtc_helper.c which has a lot of driver callbacks and is written with
the usual bread of hw found on desktop gpus in mind. I guess for a lot of
hardware this is simply the wrong abstraction level and interfacing a bit
higher up (e.g. at the level of drm_crtc_helper_set_mode) could be much
more appropriate.

And of course there's always the option of just rolling your own
infrastructure like i915.ko now does.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch