On Fri, 27 Apr 2012 16:24:24 +0100
Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Thu, 26 Apr 2012 16:03:08 -0700, Ben Widawsky <ben at bwidawsk.net>
> wrote:
> > This helps implement glClientWaitSync.
> >
> > Finally we can use the new timed seqno waiting function to allow
> > userspace to wait on a request with a timeout. This implements that
> > interface.
> >
> > The new ioctl is very straight forward, there is a flags field
> > which I envision may be useful for various flush permutations of
> > the command.
>
> What are the semantics of the ioctl? A simple use case would help
> specify the interface here.
The first time I sent out the series, I included the libdrm and igt
test. Is this what you're looking for, or something in the commit
message?
>
> In particular, I can't tell whether the return value (timeout_ns) is
> meant to be the time elapsed or the time remaining. What value is
> returned in the timeout if we are interrupted before the wait
> completes? Would
> end = gettimeofday() + timeout;
> do {
> ret = i915_gem_wait(handle, 0, &timeout);
> } while (ret == -1 && errno == EINTR);
> assert(gettimeofday() <= end);
> wait forever, or until the original timeout expires?
> -Chris
>
The return value should give the remaining time left if the return value
was not 0, though I venture to guess you're Socratically trying to tell
me something, so I'll go through this again and find the bug.
