[Mesa-dev] egl/android: fence_fd being forced to -1

[Eric Engestrom]

On Thursday, 2017-06-15 16:17:20 -0400, Rob Clark wrote:
> On Thu, Jun 15, 2017 at 1:17 PM, Tapani Pälli <tapani.palli at intel.com> wrote:
> > On 06/15/2017 07:57 PM, Rob Clark wrote:
> >
> > On Thu, Jun 15, 2017 at 12:04 PM, Tapani Pälli <tapani.palli at intel.com>
> > wrote:
> >
> > On 06/15/2017 06:52 PM, Rob Clark wrote:
> >
> > On Thu, Jun 15, 2017 at 9:59 AM, Eric Engestrom
> > <eric.engestrom at imgtec.com> wrote:
> >
> > On Thursday, 2017-06-15 13:27:06 +0000, Marathe, Yogesh wrote:
> >
> > Hello,
> >
> > I'm tyring to run flatland native app on android. It apparantly fails
> > because of a fence issue.
> > while debuging further it is observed that droid_window_enqueue_buffer()
> > is forcing
> > fence_fd =-1.
> >
> > Yogesh, can you describe a bit more what "fails" means?  What sequence
> > of gl calls, for example, is it making?
> >
> >
> > The problem described shortly: Flatland uses timestamps from Fence objects
> > for calculating time (using getSignalTime API) and in case of having -1 from
> > producer (Mesa) we will end up having same timestamp for startFence and
> > endFence (since both are Fence::NO_FENCE) and thus flatland will keep
> > running forever as it thinks no time has been passed between 2 fences. It is
> > stuck in a loop where it tries to find how many frames are required so that
> > driver will spend certain amount of time doing it.
> >
> > hmm, any idea what the getSignalTime() API sits on top of?  I don't
> > think we have such a capability with fence fd's..
> >
> >
> > I don't know much of libsync but it uses libsync functions 'sync_fence_info'
> > and 'sync_pt_info' to retrieve data from fence fd.
> >
> 
> oh, yeah, upstream does look like it supports the SYNC_IOC_FILE_INFO
> ioctl.  So I guess someone did actually think this through ;-)

If memory serves, Gustavo Padovan did most of that work :)