From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keith Packard Subject: Re: [PATCH] drm/i915: paper over missed irq issues with force wake vodoo Date: Sat, 14 Jan 2012 22:35:44 -0800 Message-ID: <861ur14gn3.fsf@sumi.keithp.com> References: <1325702445-2231-1-git-send-email-daniel.vetter@ffwll.ch> <86lipb367b.fsf@sumi.keithp.com> <20120113235231.GE3843@phenom.ffwll.local> <86k44v3zy8.fsf@sumi.keithp.com> <20120114003140.GG3843@phenom.ffwll.local> <86boq73y5c.fsf@sumi.keithp.com> <20120114121152.GA3583@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============0216604195==" Return-path: Received: from keithp.com (home.keithp.com [63.227.221.253]) by gabe.freedesktop.org (Postfix) with ESMTP id 12E929E710 for ; Sat, 14 Jan 2012 22:35:51 -0800 (PST) In-Reply-To: <20120114121152.GA3583@phenom.ffwll.local> 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: Daniel Vetter Cc: Daniel Vetter , intel-gfx , Eugeni Dodonov , stable@kernel.org List-Id: intel-gfx@lists.freedesktop.org --===============0216604195== Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" --=-=-= Content-Transfer-Encoding: quoted-printable On Sat, 14 Jan 2012 13:12:07 +0100, Daniel Vetter wrote: > I think that race is air-tight with your patch to rework the reset code > already. But better safe than sorry. And as I've said a good cleanup > anyway. Sounds good. I like clearer code, especially when it doesn't cost performance. I think I'd like my version in -fixes so that we don't change anything with -next; no reason to have two slightly different versions out there in case one (or the other) is broken? > One of the reasons Chris originally shot down Ben's forcewake patches > which protected everything with a spinlock (i.e. also writes) is the > overhead. And writes to advance the ring are actually rather common. Iirc > Chris even wrote a patch to cut down on the overhead by caching the fifo > count. So I think we actually want this asymmetry in locking for > performance reasons. Ah, that's a good reason to use different locking for each path then. Suitable documentation, and a WARN_ON in the write path to check for the struct_mutex should suffice to prevent mistakes in the future. =2D-=20 keith.packard@intel.com --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIVAwUBTxJzwTYtFsjWk68qAQhCXQ/9EGWml/tMPDItr/epQawS1+SFGFvM2zUN eZToDYwaRObc0R6zEx2+wFxrr7rxhtDph1Ji5nvO+OQztPI8OpWnYTyalIV/W+3p Ls3B+HJTzbbFqbKJSr4O53T0o6+uvNk+NWTsO+XmbZgF7dtnaTT7bfYQW5uqmxEh Yj3kQgm/2592+zl+voimqY0lGYsOnMAUgWDBouP4L/cf1mI0mdbdPVLsRABFihXx Gle00uGGx2Cup9na5oH/GcjmuIrYzJ2t4Av9yidmaHYDllh7X7YQSEzX6ZfYbgO2 rYWyoWc4+/UHdmflDtiFAd56COS+0ULbIieTbtopf/U1GG5+X1mfOaqaLZyZtVEh 5R9GxYyrwXuz+BF6bshc5sex+mcy0K8Nu7DgjgX2W9aSF0NmGLjyD2Lcv44PtqnP PP4bRmy/2u/xpvPm7M9/+d5VBWpFaWsRJWt3eIr/gJXHT8afgty50cLgRCgwGISe HPJWbwQG+fC7y5mRPi5dnGjLTHPt4Tj1B47cBsEzG4tyJmLfx/Wnh/kMAevTy/Gb JtYfm3N7rcNG6AGFfHGRYn1iJVmWN0VoK6MNinBDAXtgXMNpZ3hzCVQqAxwaBmSb rr2NaZXASPLRXN1YrGxRj98C09MTBBAAgJ9fWHG+NQ4TNBYUPG97HPbst0kj7f40 AbieDeNC6Js= =j0E0 -----END PGP SIGNATURE----- --=-=-=-- --===============0216604195== 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 --===============0216604195==--