[Intel-gfx] [PATCH] drm/i915: disable cloning on sdvo

[Daniel Vetter]

On Fri, Nov 16, 2012 at 02:48:36PM -0200, Paulo Zanoni wrote:
> Hi
> 
> 2012/11/16 Daniel Vetter <daniel at ffwll.ch>:
> > On Fri, Nov 16, 2012 at 12:04:35PM -0200, Paulo Zanoni wrote:
> >> Hi
> >>
> >> 2012/11/13 Daniel Vetter <daniel.vetter at ffwll.ch>:
> >> > After the recent pile of disable-cloning patches, e.g.
> >> >
> >> > commit e3b86d6941c7e5f90be05d986fce1fcb40c68d6b
> >> > Author: Egbert Eich <eich at suse.de>
> >> > Date:   Sat Oct 13 14:30:15 2012 +0200
> >> >
> >> >     DRM/i915: Don't clone SDVO LVDS with analog
> >> >
> >> > and a bug report from Chris Wilson indicating that cloning doesn't
> >> > even work for DVI-SDVO and native VGA, let's just disable cloning on
> >> > sdvo encoders completely.
> >> >
> >> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=29259
> >> > Tested-by: Chris Wilson <chris at chris-wilson.co.uk>
> >> > Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> >> > ---
> >> >  drivers/gpu/drm/i915/intel_sdvo.c |   12 +++++-------
> >> >  1 file changed, 5 insertions(+), 7 deletions(-)
> >> >
> >> > diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
> >> > index d6a5fb9..909d34f 100644
> >> > --- a/drivers/gpu/drm/i915/intel_sdvo.c
> >> > +++ b/drivers/gpu/drm/i915/intel_sdvo.c
> >> > @@ -2208,7 +2208,6 @@ intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
> >> >                 connector->connector_type = DRM_MODE_CONNECTOR_HDMIA;
> >> >                 intel_sdvo->is_hdmi = true;
> >> >         }
> >> > -       intel_sdvo->base.cloneable = true;
> >> >
> >> >         intel_sdvo_connector_init(intel_sdvo_connector, intel_sdvo);
> >> >         if (intel_sdvo->is_hdmi)
> >> > @@ -2239,7 +2238,6 @@ intel_sdvo_tv_init(struct intel_sdvo *intel_sdvo, int type)
> >> >
> >> >         intel_sdvo->is_tv = true;
> >> >         intel_sdvo->base.needs_tv_clock = true;
> >> > -       intel_sdvo->base.cloneable = false;
> >> >
> >> >         intel_sdvo_connector_init(intel_sdvo_connector, intel_sdvo);
> >> >
> >> > @@ -2282,8 +2280,6 @@ intel_sdvo_analog_init(struct intel_sdvo *intel_sdvo, int device)
> >> >                 intel_sdvo_connector->output_flag = SDVO_OUTPUT_RGB1;
> >> >         }
> >> >
> >> > -       intel_sdvo->base.cloneable = true;
> >> > -
> >> >         intel_sdvo_connector_init(intel_sdvo_connector,
> >> >                                   intel_sdvo);
> >> >         return true;
> >> > @@ -2314,9 +2310,6 @@ intel_sdvo_lvds_init(struct intel_sdvo *intel_sdvo, int device)
> >> >                 intel_sdvo_connector->output_flag = SDVO_OUTPUT_LVDS1;
> >> >         }
> >> >
> >> > -       /* SDVO LVDS is not cloneable because the input mode gets adjusted by the encoder */
> >> > -       intel_sdvo->base.cloneable = false;
> >> > -
> >> >         intel_sdvo_connector_init(intel_sdvo_connector, intel_sdvo);
> >> >         if (!intel_sdvo_create_enhance_property(intel_sdvo, intel_sdvo_connector))
> >> >                 goto err;
> >> > @@ -2726,6 +2719,11 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob)
> >> >                 goto err_output;
> >> >         }
> >> >
> >> > +       /* SDVO because we need different clocks for SDVO encoders compared to
> >> > +        * VGA. And the sdvo encoder is also allowed to adjust the mode. So just
> >> > +        * give up and disable it. */
> >>
> >> The code looks good, but the comment above is quite confusing. "SDVO because"?
> >
> > Oops. What about:
> >
> > "Cloning SDVO with anything is often impossible, since the SDVO encoder
> > can request a special input timing mode. And even if that's not the case
> > we have evidence that cloning a plain unscaled mode with VGA doesn't
> > really work. Furthermore the cloning flags are way to simplistic anyway to
> 
> s/way to simplistic/way too simplistic/ ?
> 
> > express such constraints, so just give up on cloning for SDVO encoders."
> >
> > Is that good enough for a full r-b?
> 
> Yes. A simple "this doesn't work, maybe our code is bugged, maybe not,
> so disable it anyway" would also have done the job :)
> 
> Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>

Applied to -fixes, with the new comment (and the spelling fixed in the
comment). Thanks for the review.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch