From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: [Intel-gfx] [PATCH 15/19] drm: Update vblank->last in drm_update_vblank_count() Date: Wed, 6 Aug 2014 16:30:29 +0300 Message-ID: <20140806133029.GT4193@intel.com> References: <1407325803-6944-1-git-send-email-ville.syrjala@linux.intel.com> <1407325803-6944-16-git-send-email-ville.syrjala@linux.intel.com> <20140806130825.GH8727@phenom.ffwll.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: <20140806130825.GH8727@phenom.ffwll.local> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Daniel Vetter Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org On Wed, Aug 06, 2014 at 03:08:25PM +0200, Daniel Vetter wrote: > On Wed, Aug 06, 2014 at 02:49:58PM +0300, ville.syrjala@linux.intel.com w= rote: > > From: Ville Syrj=E4l=E4 > > = > > We should update the last in drm_update_vblank_count() to avoid applying > > the diff more than once. This could occur eg. if drm_vblank_off() gets > > called multiple times for the crtc. > > = > > Signed-off-by: Ville Syrj=E4l=E4 > = > Currently we update ->last when disabling the vblank and use it when > re-enabling it. Those calls should be symmetric, except for driver bugs. > Imo would be better to tighten up the checks for that. > = > Or do I completely misunderstand what's going on here? The issue is that we want to call drm_vblank_off() in intel_sanitize_crtc() for already disabled crtcs in order to to bump the refcount and set inmodeset=3D1 so that drm_vblank_get() won't try to enable vblank interrupts if someone calls drm_vblank_get() on it. So during suspend+resume we can get two drm_vblank_off() calls for the same crtc w/o a drm_vblank_on() in between. Although this patch doesn't actually fix the problem really since vblank counter query during sanitize will just return 0 because the pipe isn't active, so there's a later patch to just override .last=3D0 in intel_sanitize_crtc(). Another approach might be to set .last=3D0 in drm_vblank_off() itself (after vblank_disable_and_save()), mainly just to hide the details from the caller. > -Daniel > = > > --- > > drivers/gpu/drm/drm_irq.c | 2 ++ > > 1 file changed, 2 insertions(+) > > = > > diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c > > index 0523f5b..67507a4 100644 > > --- a/drivers/gpu/drm/drm_irq.c > > +++ b/drivers/gpu/drm/drm_irq.c > > @@ -109,6 +109,8 @@ static void drm_update_vblank_count(struct drm_devi= ce *dev, int crtc) > > if (diff =3D=3D 0) > > return; > > = > > + vblank->last =3D cur_vblank; > > + > > /* Reinitialize corresponding vblank timestamp if high-precision query > > * available. Skip this step if query unsupported or failed. Will > > * reinitialize delayed at next vblank interrupt in that case. > > -- = > > 1.8.5.5 > > = > > _______________________________________________ > > Intel-gfx mailing list > > Intel-gfx@lists.freedesktop.org > > http://lists.freedesktop.org/mailman/listinfo/intel-gfx > = > -- = > Daniel Vetter > Software Engineer, Intel Corporation > +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- = Ville Syrj=E4l=E4 Intel OTC