From: Daniel Vetter <daniel@ffwll.ch>
To: "Lawrynowicz, Jacek" <jacek.lawrynowicz@intel.com>
Cc: "intel-gfx@lists.freedesktop.org" <intel-gfx@lists.freedesktop.org>
Subject: Re: TIMESTAMP register
Date: Tue, 17 Apr 2012 23:04:18 +0200 [thread overview]
Message-ID: <20120417210418.GS4104@phenom.ffwll.local> (raw)
In-Reply-To: <36D38C1F74839847A52A484C31F3E51A154A12B9@IRSMSX101.ger.corp.intel.com>
On Tue, Apr 17, 2012 at 08:34:11PM +0000, Lawrynowicz, Jacek wrote:
> ARB_timer_query allows client read TIMESTAMP both asynchronously and synchronously.
> The former can be implemented as you said but the latter requires support from the KMD.
> This must be a simple MMIO read as this is the only way to report "current" GPU time.
> Implementing synchronous TIMESTAMP query using pipe control would render the third example from ARB_timer_query spec useless.
Ok, I've looked like a dofus again, but now I've read the spec and we
indeed seem to need a synchronous readout of the TIMESTAMP register. I
guess a new register will do, together with some fixed-point integer that
tells userspace how to convert it to nanoseconds.
-Daniel
--
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48
next prev parent reply other threads:[~2012-04-17 21:03 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-17 19:12 TIMESTAMP register Lawrynowicz, Jacek
2012-04-17 19:39 ` Daniel Vetter
2012-04-17 20:34 ` Lawrynowicz, Jacek
2012-04-17 21:04 ` Daniel Vetter [this message]
2012-04-17 23:27 ` Ben Widawsky
2012-04-17 23:51 ` Chris Wilson
2012-04-18 6:32 ` Lawrynowicz, Jacek
2012-04-18 7:35 ` Chris Wilson
2012-04-18 7:53 ` Lawrynowicz, Jacek
2012-04-18 8:05 ` Chris Wilson
2012-04-30 21:11 ` Eric Anholt
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