[Intel-gfx] [RFC] i915: Add fence fds to execbuffer2 uapi

[John Harrison]

On 27/06/2016 21:18, Chad Versace wrote:
> On Mon 27 Jun 2016, Chad Versace wrote:
>> Let the hight 32 bits of drm_i915_gem_execbuffer2::rsvd1 contain an
>> input and/or output fence fd, whose presence is controlled by flags.
>> Also add I915_PARAM_HAS_FENCE_FD.
>>
>> Signed-off-by: Chad Versace <chad.versace at intel.com>
>> ---
>>   include/uapi/drm/i915_drm.h | 24 ++++++++++++++++++++++--
>>   1 file changed, 22 insertions(+), 2 deletions(-)
> Oops. git-send-email stripped the notes to the patch. Here's the notes:
>
> This RFC proposes a uapi that integrates execbuf with Android sync fds.  Of
> course, this is *only* an RFC because other devs are working on the i915
> internals, and this patch depends on that work.
>
> Why am I sending an RFC this early? I will soon begin prototyping Intel's
> Mesa implementation of EGL_ANDROID_native_fence_sync, and that prototype will
> be easier to write if I have a rough expectation of i915's eventual fence fd
> uapi.
>
> Please provide feedback: Does this roughly look like the uapi that the i915
> devs expect?
>
> (Pardon any stupidity in the patch. It's my first non-trivial kernel patch).
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Not sure who you mean by 'the devs' but I am the one who implemented all 
of this for our Android releases. I have a patch series to add full 
native sync support to the i915 driver. It is currently used in our 
Android trees so has been tested quite extensively. It was also going 
through code review on the mailing list a while ago until it was decided 
that the de-staging of the Android code should be done by external 
people (currently in progress).

The latest set of patches (including changes from feedback about rsvd 
fields) never actually got posted to the mailing list due to the above 
issue with de-staging. I have just updated my FDO git account with them 
instead. The kernel patch is:
https://cgit.freedesktop.org/~johnharr/scheduler/commit/?h=all&id=b7cd5e85edce4af9d7d4c34bb640cd49e31236a8

The userland LibDRM patch is:
https://cgit.freedesktop.org/~johnharr/scheduler/commit/?h=LibDRM&id=f11b2d577904b1a096d5b36384a9cc83ba51cbb8


John.