From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH 1/2] drm/i915: remove unexplained vblank wait in the DP off code Date: Tue, 22 Apr 2014 21:17:18 +0200 Message-ID: <20140422191718.GB10722@phenom.ffwll.local> References: <20140405062638.GD8475@nuc-i3427.alporthouse.com> <1397251542-6857-1-git-send-email-jbarnes@virtuousgeek.org> <20140417122127.GS18465@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Received: from mail-ee0-f42.google.com (mail-ee0-f42.google.com [74.125.83.42]) by gabe.freedesktop.org (Postfix) with ESMTP id BA9816E59B for ; Tue, 22 Apr 2014 12:17:22 -0700 (PDT) Received: by mail-ee0-f42.google.com with SMTP id d17so48514eek.1 for ; Tue, 22 Apr 2014 12:17:22 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20140417122127.GS18465@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Cc: intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Thu, Apr 17, 2014 at 03:21:27PM +0300, Ville Syrj=E4l=E4 wrote: > On Fri, Apr 11, 2014 at 02:25:41PM -0700, Jesse Barnes wrote: > > I don't think this is necessary; at least it doesn't appear to be on my > > BYT. Dropping it speeds up our shutdown code a little, in some cases > > resulting in faster init times. > > = > > Signed-off-by: Jesse Barnes > > --- > > drivers/gpu/drm/i915/intel_dp.c | 3 --- > > 1 file changed, 3 deletions(-) > > = > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/int= el_dp.c > > index e48d47c..728a5db 100644 > > --- a/drivers/gpu/drm/i915/intel_dp.c > > +++ b/drivers/gpu/drm/i915/intel_dp.c > > @@ -2756,9 +2756,6 @@ intel_dp_link_down(struct intel_dp *intel_dp) > > } > > POSTING_READ(intel_dp->output_reg); > > = > > - /* We don't really know why we're doing this */ > > - intel_wait_for_vblank(dev, intel_crtc->pipe); > > - > = > Maybe this was here to guarantee we send the magic five idle patterns > specified in the DP spec. But since we're going to be turning off the > port anyway I don't see why we switch to transmitting the idle pattern > at all. > = > I guess switching to the idle pattern might make sense for the IBX > transcoder select workaround to avoid sending some garbage on the main > link. Although we don't seem to be doing that workaround quite according > to spec. The spec says we should first disable the port, and then > re-enable it temporarily w/ transcoder A. What we do is switch the port > over to transcoder A while it's still enabled, and only then disable it. > = > So I guess killing the wait here is fine, but looks like the IBX > workaround stuff needs a better look. I can try to clean it up a bit. > = > Reviewed-by: Ville Syrj=E4l=E4 Queued for -next, thanks for the patch. -Daniel -- = Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch