From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Anholt Subject: Re: No more read/write ioctls Date: Fri, 08 Apr 2011 07:10:14 -1000 Message-ID: <87fwpsfz49.fsf@pollan.anholt.net> References: <1301621965-23185-1-git-send-email-ben@bwidawsk.net> <1301702089-25644-1-git-send-email-ben@bwidawsk.net> <20110406213826.GA32472@snipes.kumite> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1183375208==" Return-path: In-Reply-To: <20110406213826.GA32472@snipes.kumite> 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: Ben Widawsky , intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org --===============1183375208== Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" --=-=-= Content-Transfer-Encoding: quoted-printable On Wed, 6 Apr 2011 14:38:27 -0700, Ben Widawsky wrote: > On Fri, Apr 01, 2011 at 04:54:47PM -0700, Ben Widawsky wrote: >=20 > > So if this isn't okay by everyone, let's get down to the minimum number > > of changes required to get this accepted so I can move on to the tools, > > and then get back to the debug stuff. > >=20 >=20 > Some discussion on IRC has led to a new proposal (well 2 new proposals, > but the first one wasn't viable). >=20 > The interface will instead of using ioctls use debugfs. The debugfs file > will control force wake. There will be a refcount mechanism for number > of users of the registers in the relevant power-well, and upon opening a > specific file in debugfs (we could have one per power-well if needed), > the refcount will get incremented, and decremented at close. >=20 > In other words, for userspace to read/write registers: > fd =3D open(/sys/kernel/debug/dri...) > normal read write mechanism > close(fd) >=20 > There are two side effects which everyone on IRC seems fine with: > * root-only read access (the ioctl read was promiscuous) > * access is only available when debugfs is mounted >=20 > As a result, you should ignore both the gpu-tools patches, as well as > these kernel patches. I thought previously we had issues with debugfs nodes which could wedge the system (out of range mmio reads)? --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iEYEARECAAYFAk2fQXYACgkQHUdvYGzw6veccgCgkVuXVqA4BZuyI3D5rUjqI7Xv xWEAn2NXV/tb8eEaYchWNl4DU0cwEqZT =lsFV -----END PGP SIGNATURE----- --=-=-=-- --===============1183375208== 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 --===============1183375208==--