[RFC PATCH 00/12] Ion cleanup in preparation for moving out of staging

On 03/03/2017 08:45 AM, Laurent Pinchart wrote:

Hi Daniel,

On Friday 03 Mar 2017 11:04:33 Daniel Vetter wrote:

quoted

On Thu, Mar 02, 2017 at 01:44:32PM -0800, Laura Abbott wrote:

quoted

Hi,

There's been some recent discussions[1] about Ion-like frameworks. There's
apparently interest in just keeping Ion since it works reasonablly well.
This series does what should be the final clean ups for it to possibly be
moved out of staging.

This includes the following:
- Some general clean up and removal of features that never got a lot of
  use as far as I can tell.

- Fixing up the caching. This is the series I proposed back in December[2]
  but never heard any feedback on. It will certainly break existing
  applications that rely on the implicit caching. I'd rather make an
  effort to move to a model that isn't going directly against the
  establishement though.

- Fixing up the platform support. The devicetree approach was never well
  recieved by DT maintainers. The proposal here is to think of Ion less as
  specifying requirements and more of a framework for exposing memory to
  userspace.

- CMA allocations now happen without the need of a dummy device structure.
  This fixes a bunch of the reasons why I attempted to add devicetree
  support before.

I've had problems getting feedback in the past so if I don't hear any
major objections I'm going to send out with the RFC dropped to be picked
up. The only reason there isn't a patch to come out of staging is to
discuss any other changes to the ABI people might want. Once this comes
out of staging, I really don't want to mess with the ABI.

Feedback appreciated.

Imo looks all good. And I just realized that cross-checking with the TODO,
the 2 items about _CUSTOM and _IMPORT ioctls I noted are already there.

Otherwise I looked through the patches, looks all really reasonable.

Two more items that need to be addressed in my opinion :

- Let's not export the ion_client API, we don't want drivers to be ion-
specific. Only the dma-buf interface should be visible to drivers.

Yes, that's a good point. I never heard back from anyone about a need for
in kernel allocation via Ion.

Thanks,
Laura