[Intel-gfx] [PATCH v2] drm/i915/fbdev: Enable late fbdev initial configuration

[Souza, Jose]

On Thu, 2018-04-19 at 15:50 +0300, Jani Nikula wrote:
> On Wed, 18 Apr 2018, José Roberto de Souza <jose.souza at intel.com>
> wrote:
> > If the initial fbdev configuration(intel_fbdev_initial_config())
> > runs and
> > there still no sink connected it will cause
> > drm_fb_helper_initial_config() to return 0 as no error happened(but
> > internally the return is -EAGAIN).
> > Because no framebuffer was allocated, when a sink is connected
> > intel_fbdev_output_poll_changed() will not execute
> > drm_fb_helper_hotplug_event() that would trigger another try to do
> > the
> > initial fbdev configuration.
> > 
> > So here allowing drm_fb_helper_hotplug_event() to be executed when
> > there
> > is not frambebuffer allocated and fbdev was not setup yet.
> > 
> > This issue also happens when a MST DP sink is connected since boot,
> > as
> > the MST topology is discovered in parallel if
> > intel_fbdev_initial_config()
> > is executed before the first sink MST is discovered it will cause
> > this
> > same issue.
> > 
> > This is a follow up patch of
> > https://patchwork.freedesktop.org/patch/196089/
> 
> What does this mean? Is that patch a required dependency? What?

No requirement, this is just a follow up patch of that one, that patch
was not accepted and Chris did a suggestion that was implemented in the
first version.

> 
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104158
> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=104425
> 
> People responded to v1, please ask them to test v2.

Okay, I just asked people to test the version 2 but I'm also able to
reproduce the issue and it was already tested.

> 
> > Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > ---
> > 
> > Changes from v1:
> > - not creating a dump framebuffer anymore, instead just allowing
> > drm_fb_helper_hotplug_event() to execute when fbdev is not setup
> > yet.
> 
> Please look at git log in drm, and observe how we include the
> changelog
> in the commit message itself.

Okay, I will do that from now on.

> 
> BR,
> Jani.
> 
> > 
> >  drivers/gpu/drm/i915/intel_fbdev.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_fbdev.c
> > b/drivers/gpu/drm/i915/intel_fbdev.c
> > index 7d41d139341b..e9e02b58b7be 100644
> > --- a/drivers/gpu/drm/i915/intel_fbdev.c
> > +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> > @@ -807,7 +807,7 @@ void intel_fbdev_output_poll_changed(struct
> > drm_device *dev)
> >  		return;
> >  
> >  	intel_fbdev_sync(ifbdev);
> > -	if (ifbdev->vma)
> > +	if (ifbdev->vma || ifbdev->helper.deferred_setup)
> >  		drm_fb_helper_hotplug_event(&ifbdev->helper);
> >  }
> 
>