From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Anholt Subject: Re: Questions about libdrm_intel and way to share physical memory between CPU and GPU Date: Fri, 03 Jun 2011 20:32:09 -0700 Message-ID: <8762ome0g6.fsf@eliezer.anholt.net> References: <5812F7DC54903547874AA228AE9C46AB7D8957F8@orsmsx504.amr.corp.intel.com> <20110602194203.7a72ea60@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1990843907==" Return-path: In-Reply-To: <20110602194203.7a72ea60@lxorguk.ukuu.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: Alan Cox , Chris Wilson Cc: "dri-devel@lists.freedesktop.org" List-Id: dri-devel@lists.freedesktop.org --===============1990843907== Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" --=-=-= Content-Transfer-Encoding: quoted-printable On Thu, 2 Jun 2011 19:42:03 +0100, Alan Cox wrot= e: > On Sat, 28 May 2011 09:54:01 +0100 > Chris Wilson wrote: >=20 > > On Fri, 27 May 2011 14:37:45 -0700, "Segovia, Benjamin" wrote: > > > Hello gurus, > > >=20 > > > I have two question mostly regarding libdrm_intel > > >=20 > > > 1/ What is the difference between drm_intel_bo_map and drm_intel_gem_= bo_map_gtt ? > > bo_map uses the CPU domain, and so is CPU linear (needs sw detiling). > > bo_gtt_map uses the uncached [WC] GTT domain, and so is GPU linear > > (detiling is performed by the hardware using a fence). > >=20 > > > 2/ Will it be possible (or is it already possible) to directly share = a regularly allocated piece of physical memory? Typical use case is the fol= lowing one using OpenCL API: > >=20 > > Yes. I've proposed a vmap interface to bind user-pages into the GTT, > > similar to a completely unused bit of TTM functionality. >=20 > It seems to me that stolen memory and other things could all be sorted > out somewhat if the GEM layer and GEM as shmemfs backing were split apart > a bit. A 'privately backed' GEM object wouldn't be able to support > flink() but I can't find much else that would break ? >=20 > Wondering about this for things like the GMA500, and also to get back all > that memory the i9xx driver burns on a PC. I'd much rather be able to just hand that memory off to the kernel to use along with everything else and have there be nothing magic about it. But as I recall, the mtrr mappings of that memory was often goofy, so it may take some work to clean it up. --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iEYEARECAAYFAk3ppzkACgkQHUdvYGzw6vdUSQCeKgbA46TqCHQB08zV0oNIYNP4 Cw0Anj9AJhDW0xpPFnuzTFbHQcFcM51q =c2RB -----END PGP SIGNATURE----- --=-=-=-- --===============1990843907== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/dri-devel --===============1990843907==--