From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keith Packard Subject: Re: [PATCH 3/6] drm/i915: Support write only mappings Date: Mon, 19 Sep 2011 22:29:15 -0700 Message-ID: References: <1316492706-31081-1-git-send-email-ben@bwidawsk.net> <1316492706-31081-4-git-send-email-ben@bwidawsk.net> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1985027499==" Return-path: Received: from keithp.com (home.keithp.com [63.227.221.253]) by gabe.freedesktop.org (Postfix) with ESMTP id 0FAFCA0223 for ; Mon, 19 Sep 2011 22:29:20 -0700 (PDT) In-Reply-To: <1316492706-31081-4-git-send-email-ben@bwidawsk.net> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: intel-gfx@lists.freedesktop.org Cc: Daniel Vetter , Ben Widawsky List-Id: intel-gfx@lists.freedesktop.org --===============1985027499== Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" --=-=-= Content-Transfer-Encoding: quoted-printable On Mon, 19 Sep 2011 21:25:03 -0700, Ben Widawsky wrote: > When doing a GTT mapping, the pages are not backed until taking a fault. > If we know that the object is write only, when the fault happens we do no= t need > to make the pages coherent with the CPU. This allows for semi fast prefa= ults > to occur in libdrm at map time. Every time I see this stuff, I get confused by the term 'write-only'. Reading through the code, I remind myself that what you're actually promising is that any CPU accesses to the object will not overlap any potential writes by the GPU. The CPU could be reading or writing, it really doesn't matter. Really what you want is a kernel call that does everything except block on the GPU, right? =2D-=20 keith.packard@intel.com --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iD8DBQFOeCSrQp8BWwlsTdMRAlktAJ9Ca57w1RDA8gUc+PEo/O17kX16OQCeJqNV HYPfXITPVgoJim1flvMx7j8= =XZVB -----END PGP SIGNATURE----- --=-=-=-- --===============1985027499== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx --===============1985027499==--