Re: [PATCH] drm/i915: Ignore OpRegion panel type except on select machines

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Sep 13, 2016 at 12:37:16PM +0300, Jani Nikula wrote:
> On Tue, 13 Sep 2016, ville.syrjala@linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > Turns out
> > commit a05628195a0d ("drm/i915: Get panel_type from OpRegion panel
> > details") has regressed quite a few machines. So it looks like we
> > can't use the panel type from OpRegion on all systems, and yet we
> > absolutely must use it on some specific systems.
> >
> > Despite trying, I was unable to find any automagic way to determine
> > if the OpRegion panel type is respectable or not. The only glimmer
> > of hope I had was bit 8 in the SCIC response, but that turned out to
> > not work either (it was always 0 on both types of systems).
> >
> > So, to fix the regressions without breaking the machine we know to need
> > the OpRegion panel type, let's just add a quirk for this. Only specific
> > machines known to require the OpRegion panel type will therefore use
> > it. Everyone else will fall bck to the VBT panel type.
> >
> > The only known machine so far is a "Conrac GmbH IX45GM2". The PCI
> > subsystem ID on this machine is just a generic 8086:2a42, so of no use.
> > Instead we'll go with a DMI match.
> >
> > I suspect we can now also revert
> > commit aeddda06c1a7 ("drm/i915: Ignore panel type from OpRegion on SKL")
> > but let's leave that to a separate patch.
> >
> > v2: Do the DMI match in the opregion code directly, as dev_priv->quirks
> >     gets populated too late
> >
> > Cc: Rob Kramer <rob@solution-space.com>
> > Cc: Martin van Es <martin@mrvanes.com>
> > Cc: Andrea Arcangeli <aarcange@redhat.com>
> > Cc: Dave Airlie <airlied@linux.ie>
> > Cc: Marco Krüger <krgsch@gmail.com>
> > Cc: Sean Greenslade <sean@seangreenslade.com>
> > Cc: Trudy Tective <bertslany@gmail.com>
> > Cc: Robin Müller <rm1990@gmx.de>
> > Cc: Alexander Kobel <a-kobel@a-kobel.de>
> > Cc: Alexey Shumitsky <alexey.shumitsky@gmail.com>
> > Cc: Emil Andersen Lauridsen <mine809@gmail.com>
> > Cc: oceans112@gmail.com
> > Cc: James Hogan <james@albanarts.com>
> > Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
> > Cc: stable@vger.kernel.org
> > References: https://lists.freedesktop.org/archives/intel-gfx/2016-August/105545.html
> > References: https://lists.freedesktop.org/archives/dri-devel/2016-August/116888.html
> > References: https://lists.freedesktop.org/archives/intel-gfx/2016-June/098826.html
> 
> References: http://patchwork.freedesktop.org/patch/msgid/1473602239-15855-1-git-send-email-adrienverge@gmail.com
> 
> Acked-by: Jani Nikula <jani.nikula@intel.com>
> 
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=94825
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97060
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97443
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97363
> > Fixes: a05628195a0d ("drm/i915: Get panel_type from OpRegion panel details")
> > Tested-by: Marco Krüger <krgsch@gmail.com>
> > Tested-by: Alexey Shumitsky <alexey.shumitsky@gmail.com>
> > Tested-by: Sean Greenslade <sean@seangreenslade.com>
> > Tested-by: Emil Andersen Lauridsen <mine809@gmail.com>
> > Tested-by: Robin Müller <rm1990@gmx.de>
> > Tested-by: oceans112@gmail.com
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Slapped on another tested-by and pushed to dinq. Thanks for the broad
testing, everyone.

> > ---
> >  drivers/gpu/drm/i915/intel_opregion.c | 27 +++++++++++++++++++++++++++
> >  1 file changed, 27 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
> > index adca262d591a..7acbbbf97833 100644
> > --- a/drivers/gpu/drm/i915/intel_opregion.c
> > +++ b/drivers/gpu/drm/i915/intel_opregion.c
> > @@ -1047,6 +1047,23 @@ err_out:
> >  	return err;
> >  }
> >  
> > +static int intel_use_opregion_panel_type_callback(const struct dmi_system_id *id)
> > +{
> > +	DRM_INFO("Using panel type from OpRegion on %s\n", id->ident);
> > +	return 1;
> > +}
> > +
> > +static const struct dmi_system_id intel_use_opregion_panel_type[] = {
> > +	{
> > +		.callback = intel_use_opregion_panel_type_callback,
> > +		.ident = "Conrac GmbH IX45GM2",
> > +		.matches = {DMI_MATCH(DMI_SYS_VENDOR, "Conrac GmbH"),
> > +			    DMI_MATCH(DMI_PRODUCT_NAME, "IX45GM2"),
> > +		},
> > +	},
> > +	{ }
> > +};
> > +
> >  int
> >  intel_opregion_get_panel_type(struct drm_i915_private *dev_priv)
> >  {
> > @@ -1073,6 +1090,16 @@ intel_opregion_get_panel_type(struct drm_i915_private *dev_priv)
> >  	}
> >  
> >  	/*
> > +	 * So far we know that some machined must use it, others must not use it.
> > +	 * There doesn't seem to be any way to determine which way to go, except
> > +	 * via a quirk list :(
> > +	 */
> > +	if (!dmi_check_system(intel_use_opregion_panel_type)) {
> > +		DRM_DEBUG_KMS("Ignoring OpRegion panel type (%d)\n", ret - 1);
> > +		return -ENODEV;
> > +	}
> > +
> > +	/*
> >  	 * FIXME On Dell XPS 13 9350 the OpRegion panel type (0) gives us
> >  	 * low vswing for eDP, whereas the VBT panel type (2) gives us normal
> >  	 * vswing instead. Low vswing results in some display flickers, so
> 
> -- 
> Jani Nikula, Intel Open Source Technology Center

-- 
Ville Syrjälä
Intel OTC
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