Re: [PATCH 2/2] drm/i915: ignore bios output config if not all outputs are on

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Mar 04, 2014 at 12:33:01PM -0800, Jesse Barnes wrote:
> On Tue,  4 Mar 2014 21:08:42 +0100
> Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> 
> > Both Ville and QA rather immediately complained that with the new
> > initial_config logic from Jesse not all outputs get enabled. Since the
> > fbdev emulation pretty much tries to always enable as many outputs as
> > possible (it even has hotplug handling and all that) fall back if more
> > outputs could have been enabled.
> > 
> > v2: Fix up my confusion about what enabled means - it's passed from
> > the fbdev helper, we need to check for a non-zero connector->encoder
> > link. Spotted by Ville.
> > 
> > Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75552
> > Tested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> > ---
> >  drivers/gpu/drm/i915/intel_fbdev.c | 17 +++++++++++++++++
> >  1 file changed, 17 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
> > index df00e6b01f0d..c1a20c3babde 100644
> > --- a/drivers/gpu/drm/i915/intel_fbdev.c
> > +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> > @@ -290,6 +290,8 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
> >  	int i, j;
> >  	bool *save_enabled;
> >  	bool fallback = true;
> > +	int num_connectors_enabled = 0;
> > +	int num_connectors_detected = 0;
> >  
> >  	/*
> >  	 * If the user specified any force options, just bail here
> > @@ -324,6 +326,10 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
> >  
> >  		fb_conn = fb_helper->connector_info[i];
> >  		connector = fb_conn->connector;
> > +
> > +		if (connector->status == connector_status_connected)
> > +			num_connectors_detected++;
> > +
> >  		if (!enabled[i]) {
> >  			DRM_DEBUG_KMS("connector %d not enabled, skipping\n",
> >  				      connector->base.id);
> > @@ -338,6 +344,8 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
> >  			continue;
> >  		}
> >  
> > +		num_connectors_enabled++;
> > +
> >  		new_crtc = intel_fb_helper_crtc(fb_helper, encoder->crtc);
> >  
> >  		/*
> > @@ -393,6 +401,15 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
> >  		fallback = false;
> >  	}
> >  
> > +	/*
> > +	 * If the BIOS didn't enable everything it could, fall back to have the
> > +	 * same user experiencing of lighting up as much as possible like the
> > +	 * fbdev helper library.
> > +	 */
> > +	if (num_connectors_enabled != num_connectors_detected &&
> > +	    num_connectors_enabled < INTEL_INFO(dev)->num_pipes)
> > +		fallback = true;
> 
> I think we need a debug message in here so people can figure out why
> their fastboot failed with this patch included.  E.g. "some connected
> outputs weren't enabled, falling back to old behavior".
> 
> Also note that this will probably always happen in certain configs, and
> the fallback behavior won't be any better since we may not be able to
> light up everything that's attached.

Excellent suggestion, I've gone ahead and added debug output for all cases
where we fall back.
> 
> With those caveats:
> Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

Thanks for the review, both patches merged to dinq.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch