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

[Jesse Barnes]

On Tue, 4 Mar 2014 22:08:12 +0100
Daniel Vetter <daniel at ffwll.ch> wrote:

> 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 at 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 at virtuousgeek.org>
> > > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=75552
> > > Tested-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > Signed-off-by: Daniel Vetter <daniel.vetter at 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 at virtuousgeek.org>

Thinking about this some more last night, I think it would be better to
count the pipes and the connectors, and bail out if we have detected
connectors available but not enabled and some free pipes.  That would
prevent unnecessary fastboot breakage I think.

-- 
Jesse Barnes, Intel Open Source Technology Center