Re: [PATCH] drm/i915: Fixup hpd irq register setup ordering

[Daniel Vetter <daniel@ffwll.ch>]

On Mon, Dec 10, 2012 at 01:01:43PM -0800, Jesse Barnes wrote:
> On Sun,  9 Dec 2012 20:42:01 +0100
> Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> 
> > For GMCH platforms we set up the hpd irq registers in the irq
> > postinstall hook. But since we only enable the irq sources we actually
> > need in PORT_HOTPLUG_EN/STATUS, taking dev_priv->hotplug_supported_mask
> > into account, no hpd interrupt sources is enabled since
> > 
> > commit 52d7ecedac3f96fb562cb482c139015372728638
> > Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Date:   Sat Dec 1 21:03:22 2012 +0100
> > 
> >     drm/i915: reorder setup sequence to have irqs for output setup
> > 
> > Wrongly set-up interrupts also lead broken hw-based load-detection on
> > at least GM45, resulting in ghost VGA/TV-out outputs.
> 
> ..."can lead to broken"... or "also leads to" ?
> 
> > +
> > +void intel_hpd_init(struct drm_device *dev)
> > +{
> > +	struct drm_i915_private *dev_priv = dev->dev_private;
> > +
> > +	if (dev_priv->display.hpd_irq_setup)
> > +		dev_priv->display.hpd_irq_setup(dev);
> > +
> > +	/*
> > +	 * Some ports require correctly set-up hpd registers for detection to
> > +	 * work properly, e.g. VGA on gm45. Hence we can only set up the initial
> > +	 * fbdev config after hpd irqs are fully enabled. Now we should scan for
> > +	 * the initial config only once hotplug handling is enabled, but due to
> > +	 * screwed-up locking around kms/fbdev init we can't protect the fdbev
> > +	 * initial config scanning against hotplug events. Hence do this first
> > +	 * and ignore the tiny window where we will loose hotplug notifactions.
> > +	 */
> > +	intel_fbdev_initial_config(dev);
> > +
> > +	/* Only enable hotplug handling once the fbdev is fully set up. */
> > +	dev_priv->enable_hotplug_processing = true;
> > +
> > +	drm_kms_helper_poll_init(dev);
> > +}
> 
> I'd rather see these calls in load_modeset_init().  Having
> fbdev_initial_config here at least is confusing, and since poll_init
> depends on it...
> 
> With those two nits:
> 
> Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

Bikeshedded patch queued for -next, thanks for the review.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch