From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: [PATCH 5/5] drm/i915: Allow vblank interrupts during modeset and eliminate some vblank races Date: Mon, 24 Feb 2014 14:11:01 +0200 Message-ID: <20140224121101.GN3852@intel.com> References: <1393009415-27651-1-git-send-email-ville.syrjala@linux.intel.com> <1393009415-27651-6-git-send-email-ville.syrjala@linux.intel.com> <1393213735.27769.8.camel@thor.local> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: <1393213735.27769.8.camel@thor.local> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org To: Michel =?iso-8859-1?Q?D=E4nzer?= Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Mon, Feb 24, 2014 at 12:48:55PM +0900, Michel D=E4nzer wrote: > On Fre, 2014-02-21 at 21:03 +0200, ville.syrjala@linux.intel.com wrote: > > = > > We can kill of the drm_vblank_{pre,post}_modeset() calls since those are > > there simply to make drm_vblank_get() fail during a modeset. > = > Actually, their original purpose was to keep the DRM vblank counter > consistent across modesets, assuming the modeset resets the hardware > vblank counter. I see. Well, actually I really don't. The code is too funky for me to tell what it actually ends up doing. The obvious way would be to resample the hardware counter at drm_vblank_post_modeset(), which the code certainly doesn't do. But maybe it did something sensible in the past. -- = Ville Syrj=E4l=E4 Intel OTC