From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [PATCH] Revert "drm/i915: fix infinite loop at
 gen6_update_ring_freq"
Date: Wed, 23 Apr 2014 09:05:06 +0200
Message-ID: <20140423070506.GQ10722@phenom.ffwll.local>
References: <1397113487-25717-1-git-send-email-daniel.vetter@ffwll.ch>
 <20140410175043.GB7294@bwidawsk.net>
 <20140410175226.GA8164@bwidawsk.net>
 <20140411090212.GZ9262@phenom.ffwll.local>
 <CA+gsUGRgjyL4RHXuxs4vqr6fucPyQi9ushfR0-n_J7xTtAqSkQ@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <intel-gfx-bounces@lists.freedesktop.org>
Received: from mail-ee0-f51.google.com (mail-ee0-f51.google.com [74.125.83.51])
 by gabe.freedesktop.org (Postfix) with ESMTP id 1130C6E60F
 for <intel-gfx@lists.freedesktop.org>; Wed, 23 Apr 2014 00:05:11 -0700 (PDT)
Received: by mail-ee0-f51.google.com with SMTP id c13so375317eek.24
 for <intel-gfx@lists.freedesktop.org>; Wed, 23 Apr 2014 00:05:09 -0700 (PDT)
Content-Disposition: inline
In-Reply-To: <CA+gsUGRgjyL4RHXuxs4vqr6fucPyQi9ushfR0-n_J7xTtAqSkQ@mail.gmail.com>
List-Unsubscribe: <http://lists.freedesktop.org/mailman/options/intel-gfx>,
 <mailto:intel-gfx-request@lists.freedesktop.org?subject=unsubscribe>
List-Archive: <http://lists.freedesktop.org/archives/intel-gfx>
List-Post: <mailto:intel-gfx@lists.freedesktop.org>
List-Help: <mailto:intel-gfx-request@lists.freedesktop.org?subject=help>
List-Subscribe: <http://lists.freedesktop.org/mailman/listinfo/intel-gfx>,
 <mailto:intel-gfx-request@lists.freedesktop.org?subject=subscribe>
Errors-To: intel-gfx-bounces@lists.freedesktop.org
Sender: "Intel-gfx" <intel-gfx-bounces@lists.freedesktop.org>
To: Paulo Zanoni <przanoni@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>, Ben Widawsky <ben@bwidawsk.net>, Intel Graphics Development <intel-gfx@lists.freedesktop.org>, Paulo Zanoni <paulo.r.zanoni@intel.com>
List-Id: intel-gfx@lists.freedesktop.org

On Tue, Apr 22, 2014 at 06:25:12PM -0300, Paulo Zanoni wrote:
> 2014-04-11 6:02 GMT-03:00 Daniel Vetter <daniel@ffwll.ch>:
> > On Thu, Apr 10, 2014 at 10:52:26AM -0700, Ben Widawsky wrote:
> >> On Thu, Apr 10, 2014 at 10:50:43AM -0700, Ben Widawsky wrote:
> >> > On Thu, Apr 10, 2014 at 09:04:47AM +0200, Daniel Vetter wrote:
> >> > > This reverts commit 4b28a1f3ef55a3b0b68dbab1fe6dbaf18e186710.
> >> > >
> >> > > This patch duct-tapes over some issue in the current bdw rps patches
> >> > > which must wait with enabling rc6/rps until the very first batch has
> >> > > been submitted by userspace.
> >> > >
> >> > > But those patches aren't merged yet, and for upstream we need to have
> >> > > an in-kernel emission of the very first batch. I shouldn't have
> >> > > merged this patch so let's revert it again.
> >> >
> >> > I said this on the mailing last before you merged the patch.
> >>
> >> 20140402050338.GB13824@bwidawsk.net
> >
> > 20140402145813.GV7225@phenom.ffwll.local will explain things.
> 
> There's now a regression report pointing to the revert:
> https://bugs.freedesktop.org/show_bug.cgi?id=77565 .
> 
> What is the proposed solution now? Just WARN and still avoid the
> infinite loop? Or keep the infinite loop and leave the bug open?
> Disable BDW runtime PM?

I've thought that we can only hit this with the as-yet unmerged rc6
patches on bdw, so I'm really confused why this blows up now?

In any case I've thought Imre has stumbled over a similar issue on byt and
he has a fix to prevent runtime pm until the delayed rps init has run.
I've assigned the bug to him.

Still confused why this suddenly blew up ...
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch