From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com ([209.132.183.28]:50305 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752309AbcEBPLc (ORCPT ); Mon, 2 May 2016 11:11:32 -0400 Message-ID: <1462201891.22017.0.camel@redhat.com> Subject: Re: [Intel-gfx] [PATCH] drm/i915: Fix enc_to_dig_port() for MST encoders From: Lyude Paul To: Jani Nikula , Ville =?ISO-8859-1?Q?Syrj=E4l=E4?= Cc: intel-gfx@lists.freedesktop.org, Rob Clark , David Airlie , Daniel Vetter , "open list:INTEL DRM DRIVERS (excluding Poulsbo, Moorestow...), " "linux-kernel@vger.kernel.org (open list)" , stable@vger.kernel.org Date: Mon, 02 May 2016 11:11:31 -0400 In-Reply-To: <87vb31hqgw.fsf@intel.com> References: <1461778466-17747-1-git-send-email-cpaul@redhat.com> <87h9emjm03.fsf@intel.com> <20160428104009.GZ4329@intel.com> <87vb31hqgw.fsf@intel.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: I gave a short try at fixing MST audio, but it definitely looks like it's going to require quite a bit of troubleshooting and a few more patches :(. Since I can't find an immediate fix to actually make MST audio work I'm totally in favor of reverting the MST audio support for the time being On Thu, 2016-04-28 at 15:23 +0300, Jani Nikula wrote: > On Thu, 28 Apr 2016, Ville Syrjälä wrote: > > > > On Thu, Apr 28, 2016 at 09:17:00AM +0300, Jani Nikula wrote: > > > > > > On Wed, 27 Apr 2016, Lyude wrote: > > > > > > > > For MST encoders, the encoder struct is stored in the intel_dp_mst > > > > struct, not a intel_digital_port struct. > > > > > > > > This fixes issues with hotplugging MST displays that support MST audio, > > > > where hotplugging had a surprisingly good chance of accidentally > > > > overwriting other parts of the kernel leading to seemingly unrelated > > > > backtraces in sysfs, ext4, etc. > > > > > > > > Cc: stable@vger.kernel.org > > > > Signed-off-by: Lyude > > > Ugh. Just ugh. > > > > > > At a glance, it's probably this one that starts calling > > > intel_audio_codec_enable() and intel_audio_codec_disable() on DP MST: > > > > > > commit 3d52ccf52f2c51f613e42e65be0f06e4e6788093 > > > Author: Libin Yang > > > Date:   Wed Dec 2 14:09:44 2015 +0800 > > > > > >     drm/i915: start adding dp mst audio > > > > > > which has been there since v4.5. Would it be feasible for you to revert > > > the commit or change it so that it stops calling the audio codec > > > enable/disable, to verify this is the culprit? So we could add a proper > > > Fixes: line too. > > I don't particularly like making enc_to_dig_port() work on MST encoders > > because it'll likely result in the wrong thing anyway. I already asked > > before how MST audio port handling is supposed to work, but never got > > any answer. Right now, if you just use the ->primary dig_port in the > > audio paths, there's no way audio can work correctly with MST, at least > > if you enable multiple streams on the same port. > > > > So what I would do is just revert the audio calls from the MST paths and > > go back to the drawing board. > I don't mind that approach either. > > I was thinking we should probably add some dynamic type checking to > enc_to_dig_port to catch this type of bugs. > > BR, > Jani. > > > > > > > > > > > > > > The non-MST aware enc_to_dig_port() calls on platforms that might have > > > MST were added in: > > > > > > commit 51e1d83cab9988716ae68801a721f4df0aaa374b > > > Author: David Henningsson > > > Date:   Wed Aug 19 10:48:56 2015 +0200 > > > > > >     drm/i915: Call audio pin/ELD notify function > > > > > > and: > > > > > > commit 7e8275c2f2bbb384e18af37066b8b2f32b7d092f > > > Author: Libin Yang > > > Date:   Fri Sep 25 09:36:12 2015 +0800 > > > > > >     drm/i915: set proper N/CTS in modeset > > > > > > but I don't think the codec enable/disable were called on MST at that > > > time. > > > > > > Some of the problem was probably seen by Takashi in > > > > > > commit 0bdf5a05647a66dcc6394986e061daeac9b1cf96 > > > Author: Takashi Iwai > > > Date:   Mon Nov 30 18:19:39 2015 +0100 > > > > > >     drm/i915: Add reverse mapping between port and intel_encoder > > > > > > which has a comment /* intel_encoder might be NULL for DP MST */. Maybe > > > that needs to be updated to DTRT too. > > > > > > > > > Lyude, thanks for your efforts in DP MST area. Much appreciated. > > > > > > > > > BR, > > > Jani. > > > > > > > > > > > > > > > > > --- > > > >  drivers/gpu/drm/i915/intel_drv.h | 17 +++++++++++------ > > > >  1 file changed, 11 insertions(+), 6 deletions(-) > > > > > > > > diff --git a/drivers/gpu/drm/i915/intel_drv.h > > > > b/drivers/gpu/drm/i915/intel_drv.h > > > > index 4c027d6..81f2212 100644 > > > > --- a/drivers/gpu/drm/i915/intel_drv.h > > > > +++ b/drivers/gpu/drm/i915/intel_drv.h > > > > @@ -918,18 +918,23 @@ intel_attached_encoder(struct drm_connector > > > > *connector) > > > >   return to_intel_connector(connector)->encoder; > > > >  } > > > >   > > > > -static inline struct intel_digital_port * > > > > -enc_to_dig_port(struct drm_encoder *encoder) > > > > -{ > > > > - return container_of(encoder, struct intel_digital_port, > > > > base.base); > > > > -} > > > > - > > > >  static inline struct intel_dp_mst_encoder * > > > >  enc_to_mst(struct drm_encoder *encoder) > > > >  { > > > >   return container_of(encoder, struct intel_dp_mst_encoder, > > > > base.base); > > > >  } > > > >   > > > > +static inline struct intel_digital_port * > > > > +enc_to_dig_port(struct drm_encoder *encoder) > > > > +{ > > > > + if (encoder->encoder_type == DRM_MODE_ENCODER_DPMST) > > > > + return enc_to_mst(encoder)->primary; > > > > + else { > > > > + return container_of(encoder, struct intel_digital_port, > > > > +     base.base); > > > > + } > > > > +} > > > > + > > > >  static inline struct intel_dp *enc_to_intel_dp(struct drm_encoder > > > > *encoder) > > > >  { > > > >   return &enc_to_dig_port(encoder)->dp; > > > --  > > > Jani Nikula, Intel Open Source Technology Center > > > _______________________________________________ > > > Intel-gfx mailing list > > > Intel-gfx@lists.freedesktop.org > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx