From: Simon Farnsworth <simon.farnsworth@onelan.com>
To: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: Page flipping not working as expected for compositing - engineering resource available to help fix it
Date: Tue, 11 May 2010 09:40:09 +0100 [thread overview]
Message-ID: <201005110940.09692.simon.farnsworth@onelan.com> (raw)
In-Reply-To: <20100510110049.2eeff2f3@virtuousgeek.org>
On Monday 10 May 2010, Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
> What about the indirect bug? Did that also go away when you fixed the
> perms issue? If not, that sounds like a serious issue, in indirect
> mode the swap interval should still be honored I think...
In indirect mode, the swap interval was being honoured by the page flipping
code, but SwapBuffers wasn't blocking; instead, I appeared to be able to
continue to draw to the backbuffer after issuing SwapBuffers in my application.
In direct mode, SwapBuffers behaved as I'd expect - I blocked as soon as I
tried to draw, until the swap had completed.
Guessing wildly, when I SwapBuffers in a direct context, I ask the kernel to
stall me as soon as I draw to the back buffer (which is presumably still in use
as the real front buffer). When I'm in an indirect context, it's the X server
process that calls the kernel, which can't block, because that would stop it
servicing other clients, and it's not blocking me until it discovers
asynchronously that the kernel has pageflipped.
--
Simon Farnsworth
Software Engineer
ONELAN Limited
http://www.onelan.com/
prev parent reply other threads:[~2010-05-11 8:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-07 13:07 Page flipping not working as expected for compositing - engineering resource available to help fix it Simon Farnsworth
2010-05-10 11:04 ` Simon Farnsworth
2010-05-10 16:59 ` Simon Farnsworth
2010-05-10 17:57 ` Andrew Lutomirski
2010-05-10 18:00 ` Jesse Barnes
2010-05-11 8:40 ` Simon Farnsworth [this message]
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