On 09/20/2016 03:24 AM, Michel Dänzer wrote:
On 17/09/16 01:38 AM, Eric Anholt wrote:
Keith Packard <kei...@keithp.com> writes:
Hans de Goede <hdego...@redhat.com> writes:

So it looks like we really need glFinish to ensure proper ordering here
(and I've just deleted the v2 of this patchset with flush with I had

If you need glFinish, then your drivers are broken. glFlush and suitable
fences provides sufficient information to allow for synchronization
between operations without also requiring waiting for the hardware to
finish. It's a difference between getting things into the hardware
queues in the right order and waiting for those hardware queues to

glFlush by the spec does provide any guarantees that things have made it
to the kernel.  We have just assumed that, but I think the Radeon driver
may be violating that assumption these days.

No, it doesn't. It only uses the separate command submission thread for
internal flushes, e.g. when running out of space for the GPU command
stream. glFlush still results in a synchronous flush.

Hans, which drivers were you seeing the wrong order of operations with?

intel master gpu, slave output on nvidia gpu using nouveau kernel driver
and modesetting xorg driver on both gpus.

> I assume you were testing with patch 2 of the series applied?



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