On 10.03.2017 14:43, Daniel Vetter wrote:
On Thu, Mar 09, 2017 at 09:09:52PM +0200, Mikko Perttunen wrote:
On 03/09/2017 08:58 PM, Daniel Vetter wrote:
On Thu, Mar 9, 2017 at 6:57 PM, Mikko Perttunen <mperttunen@xxxxxxxxxx> wrote:
Hi everyone,
this series adds support for using sync fences as prefences and
postfences for host1x job submissions. The patches are available
as a git repository at
https://github.com/cyndis/linux/tree/host1x-fence-1
and testing code is available at
https://github.com/cyndis/host1x_test
though you may want to edit the main function to disable the
timeout tests for now as they cause a deadlock (not caused
by this series; fix upcoming).
Verified on a Jetson TX1; should go on top of the earlier
VIC series.
Some additional points:
* I noticed that the waitchk_mask field in the submit UAPI is completely
useless, and has never had any effect in the upstream kernel.
It has also not existed in the downstream kernel for many years.
We could replace it with the flags field if that is deemed
acceptable, though of course it is possible there exists some
application that fills it with some non-zero value.
If open source userspace (nouveau_dri.so) never used it, then you can
freely change it. Backwards compat guarantee in drm is only for open
source userspace (and by implication ofc anything that uses the ioctl
the same way). See:
https://dri.freedesktop.org/docs/drm/gpu/drm-uapi.html#open-source-userspace-requirements
nouveau doesn't have any host1x related code - so no, there is no
pre-existing open-source userspace that uses this :)
On that topic, do we have the nouveau patches to enable the
egl_android extension for this already published?
I assume you are referring to EGL_ANDROID_native_fence_sync; I don't know
what nouveau's status is regarding that. With this series, the host1x driver
does not yet allow other drivers access to the raw syncpoint values behind
host1x fences but that can be fixed pretty easily if/when nouveau wants to
support native syncpoint waits on Tegra.
Host1x jobs do use native waits already with this series, though.
Well you're adding new uapi to the tegra drm driver, and
EGL_ANDROID_native_fence_sync for nouveau seems like the real use-case for
this. Which means we need that, before we can merge these patches.
At least I assume that this was done for the nv blob tegra gl driver? Of
course if there's some other reasonable use-case, we can use that as open
source demonstration thing too.
-Daniel
The downstream driver doesn't actually support this UAPI; the work was
done against the testcases linked to above. My goal was to have
userspace clients use fence fds instead of raw syncpoints, which would
be cleaner and less error-prone; and allow future extensibility. I
suppose this might not be enough of a use-case though.
Now, quickly grepping through mesa and the nouveau kernel driver, it
looks like there is currently no implementation of
EGL_ANDROID_native_fence_sync, and no support for SYNC_FILE in nouveau.
Regrettably, I currently don't have the time to learn these codebases
and implement these features, so we might have to drop at least patches
2 and 3 and revisit them later.
Thanks,
Mikko.
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