[Intel-gfx] [PATCH] drm/i915: synchronize_irq() against the actual irq

[Chris Wilson]

Quoting Ville Syrjala (2019-07-02 15:49:47)
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> When eliminating our use of drm_irq_install() I failed to convert
> all our synchronize_irq() calls to consult pdev->irq instead of
> dev_priv->drm.irq. As we no longer populate dev_priv->drm.irq
> we're no longer synchronizing against anything.
> 
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Reported-by: Imre Deak <imre.deak at intel.com>
> Fixes: b318b82455bd ("drm/i915: Nuke drm_driver irq vfuncs")
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111012
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Oops.

Lots of duplication there, I don't think an

static inline void intel_synchronize_irq(struct drm_i915_private *i915)
{
	synchronize_irq(i915->drm.pdev->irq);
}

(intel_ or i915_ depending on taste)

would go amiss. Sadly kernel/irq/irqdesc.c doesn't report a bogus irq
number or else we could have marked the drm.irq as bad.

Kudos to Imre for figuring out the link as that bug report had been
worrying me, and never once did I suspect it was the irq serialisation.

All callsites converted,
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris