From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH 1/6] drm/i915: Bring UP Power Wells before disabling RC6. Date: Wed, 9 Apr 2014 15:02:27 +0200 Message-ID: <20140409130227.GN9262@phenom.ffwll.local> References: <1396900911-12415-1-git-send-email-rodrigo.vivi@gmail.com> <1396900911-12415-2-git-send-email-rodrigo.vivi@gmail.com> <20140407213620.GA19665@bwidawsk.net> <20140408124332.GH4481@intel.com> <5343F124.10108@intel.com> <20140409041302.GC2271@bwidawsk.net> <5344CAD2.3030406@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-f51.google.com (mail-ee0-f51.google.com [74.125.83.51]) by gabe.freedesktop.org (Postfix) with ESMTP id F354C6EB62 for ; Wed, 9 Apr 2014 06:02:30 -0700 (PDT) Received: by mail-ee0-f51.google.com with SMTP id c13so1854527eek.38 for ; Wed, 09 Apr 2014 06:02:29 -0700 (PDT) Content-Disposition: inline In-Reply-To: <5344CAD2.3030406@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: "S, Deepak" Cc: Ben Widawsky , intel-gfx@lists.freedesktop.org List-Id: intel-gfx@lists.freedesktop.org On Wed, Apr 09, 2014 at 09:51:38AM +0530, S, Deepak wrote: > = > = > On 4/9/2014 9:43 AM, Ben Widawsky wrote: > >On Tue, Apr 08, 2014 at 06:22:52PM +0530, S, Deepak wrote: > >> > >> > >>On 4/8/2014 6:13 PM, Ville Syrj=E4l=E4 wrote: > >>>On Mon, Apr 07, 2014 at 02:36:20PM -0700, Ben Widawsky wrote: > >>>>On Mon, Apr 07, 2014 at 05:01:46PM -0300, Rodrigo Vivi wrote: > >>>>>From: Deepak S > >>>>> > >>>>>We need do forcewake before Disabling RC6, This is what the BIOS > >>>>>expects while going into suspend. > >>>>> > >>>>>v2: updated commit message. (Daniel) > >>>>> > >>>>>Signed-off-by: Deepak S > >>>>>Signed-off-by: Rodrigo Vivi > >>>>>--- > >>>>> drivers/gpu/drm/i915/intel_pm.c | 6 ++++++ > >>>>> 1 file changed, 6 insertions(+) > >>>>> > >>>>>diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/= intel_pm.c > >>>>>index 04af065..ad2ff99 100644 > >>>>>--- a/drivers/gpu/drm/i915/intel_pm.c > >>>>>+++ b/drivers/gpu/drm/i915/intel_pm.c > >>>>>@@ -3198,8 +3198,14 @@ static void valleyview_disable_rps(struct drm= _device *dev) > >>>>> { > >>>>> struct drm_i915_private *dev_priv =3D dev->dev_private; > >>>>> > >>>>>+ /* we're doing forcewake before Disabling RC6, > >>>>>+ * This what the BIOS expects when going into suspend */ > >>>>>+ gen6_gt_force_wake_get(dev_priv, FORCEWAKE_ALL); > >>>>>+ > >>>>> I915_WRITE(GEN6_RC_CONTROL, 0); > >>>>> > >>>>>+ gen6_gt_force_wake_put(dev_priv, FORCEWAKE_ALL); > >>>>>+ > >>>>> gen6_disable_rps_interrupts(dev); > >>>>> } > >>>>> > >>>> > >>>>Isn't the forcewake done as part of I915_WRITE sufficient? > >>> > >>>Writes don't do forcewake, nor is the register even part of the > >>>VLV forcewake ranges. > >>> > >>>I guess the rationale for this patche is still a bit vague. But if it's > >>>really needed, I wonder whether we should do this same dance for !VLV > >>>too? Do we have any "GPU stuck in wrong power state after suspend" typ= e of > >>>bugs still around? > >> > >>One of suggestion form the HW team was to Bring the wells up before we > >>disable RC6 at run-time. We did see some issue when we enabled D0ix. > >> > >>I think the is a good practice to make sure we bring-up the wells befor= e we > >>disable RC6. At least this avoids the cases where wells are not up befo= re we > >>can access the Next register after disable. > > > >Ville was totally right. I do think a POSTING_READ is still sufficient. > >Don't care much either way. > > > = > If feel this patch is not adding any value. I OK dropping this patch. I think it makes a lot of sense - on the enable side we also grab the wells (in case the bios has enabled rc6 already) to make sure we change the rc6/rps state while everything is around. Can you please update your patch to also roll this out for gen6/8 rps disable functions? Thanks, Daniel -- = Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch