[Intel-gfx] [PATCH 25/49] drm/i915/bxt: Add DDI hpd handler

[Imre Deak]

On ti, 2015-03-17 at 11:52 +0100, Daniel Vetter wrote:
> On Tue, Mar 17, 2015 at 11:39:51AM +0200, Imre Deak wrote:
> > From: Shashank Sharma <shashank.sharma at intel.com>
> > 
> > This patch adds a hot plug interrupt handler function for BXT.
> > What this function typically does is:
> > 1. Check if hot plug is enabled from hot plug control register.
> > 2. Call hpd_irq_handler with appropriate trigger to detect a
> >    plug storm and schedule a bottom half.
> > 3. Clear sticky status bits in hot plug control register..
> > 
> > Reviewed-by: Satheeshakrishna M <satheeshakrishna.m at intel.com>
> > Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
> > Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_irq.c | 45 +++++++++++++++++++++++++++++++++++++++--
> >  1 file changed, 43 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> > index a51c00e..4a2f85b 100644
> > --- a/drivers/gpu/drm/i915/i915_irq.c
> > +++ b/drivers/gpu/drm/i915/i915_irq.c
> > @@ -2227,6 +2227,38 @@ static irqreturn_t ironlake_irq_handler(int irq, void *arg)
> >  	return ret;
> >  }
> >  
> > +static void bxt_hpd_handler(struct drm_device *dev, uint32_t iir_status)
> > +{
> > +	struct drm_i915_private *dev_priv = dev->dev_private;
> > +	uint32_t hp_control;
> > +	uint32_t hp_trigger;
> > +
> > +	/* Get the status */
> > +	hp_trigger = iir_status & BXT_DE_PORT_HOTPLUG_MASK;
> > +	hp_control = I915_READ(BXT_HOTPLUG_CTL);
> > +
> > +	/* Hotplug not enabled ? */
> > +	if (unlikely(!(hp_control & BXT_HOTPLUG_CTL_MASK))) {
> > +		DRM_ERROR("Interrupt when HPD disabled\n");
> > +		return;
> > +	}
> > +
> > +	DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
> > +		hp_control & BXT_HOTPLUG_CTL_MASK);
> > +
> > +	/* Check for HPD storm and schedule bottom half */
> > +	intel_hpd_irq_handler(dev, hp_trigger, hp_control, hpd_bxt);
> > +
> > +	/*
> > +	 * Todo: Save the hot plug status for bottom half before
> > +	 * clearing the sticky status bits, else the status will be
> > +	 * lost.
> > +	 */
> 
> This seems to be ok, but code to handle long/short pulse in
> intel_hpd_irq_handler seems to be missing.

Oops. Yea, that's completely missing, we need at least a new
bxt_port_to_hotplug_shift(). Will follow up with this. Why always
shuffling around the bits??:)

> And we absolutely need that for
> mst ports (I guess bxt has those?).

Yea, port B and C.

--Imre