[Intel-gfx] [PATCH 9/9] drm/i915: add bufferless execbuf ioctl

[Jesse Barnes]

On 09/04/2015 10:37 AM, Chris Wilson wrote:
> On Fri, Sep 04, 2015 at 09:59:03AM -0700, Jesse Barnes wrote:
>> We just need to pass in an address to execute and some flags, since we
>> don't have to worry about buffer relocation or any of the other usual
>> stuff.  Returns a fence to be used for synchronization.
> 
> There is no need for a flush+fence as part of the execbuf except for
> when the client requests one (having it optional in the flags as a
> syscall convenience). Just allow the client to inject fences
> when it wants and even then it may just elect to do all fencing itself
> from userspace. Kernel fencing is only interesting for interclient
> operation.

Yeah that's easy enough to add; are you thinking userspace would just be
polling periodically on some ranges?  And only requesting fences for
specific batches for blocking purposes?

Jesse