[Intel-gfx] [PATCH v2] drm/i915/icl: GSE interrupt moves from DE_MISC to GU_MISC

[Chris Wilson]

Quoting Dhinakaran Pandiyan (2018-05-25 20:43:13)
> The Graphics System Event(GSE) interrupt bit has a new location in the
> GU_MISC_INTERRUPT_{IIR, ISR, IMR, IER} registers. Since GSE was the only
> DE_MISC interrupt that was enabled, with this change we don't enable/handle
> any of DE_MISC interrupts for gen11. Credits to Paulo for pointing out
> the register change.
> 
> v2: from DK
> raw_reg_[read/write], branch prediction hint and drop platform check (Mika)
> 
> Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> [Paulo: bikesheds and rebases]
> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 31 ++++++++++++++++++++++++++++++-
>  drivers/gpu/drm/i915/i915_reg.h |  7 +++++++
>  2 files changed, 37 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index 2fd92a886789..cdbc23b21df6 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -2943,6 +2943,26 @@ gen11_gt_irq_handler(struct drm_i915_private * const i915,
>         spin_unlock(&i915->irq_lock);
>  }
>  
> +static void
> +gen11_gu_misc_irq_handler(struct drm_i915_private *dev_priv,
> +                         const u32 master_ctl)
> +{
> +       void __iomem * const regs = dev_priv->regs;
> +       u32 iir;
> +
> +       if (!(master_ctl & GEN11_GU_MISC_IRQ))
> +               return;
> +
> +       iir = raw_reg_read(regs, GEN11_GU_MISC_IIR);
> +       if (likely(iir)) {
> +               raw_reg_write(regs, GEN11_GU_MISC_IIR, iir);
> +               if (iir & GEN11_GU_MISC_GSE)
> +                       intel_opregion_asle_intr(dev_priv);
> +               else
> +                       DRM_ERROR("Unexpected GU Misc interrupt 0x%08x\n", iir);

You should be re-enabling the master interrupt *before* doing any work.
No?

Keeping the master interrupt disabled stops all other CPUs from
processing our interrupts; e.g. basically stopping us feeding the GPU
with work while we wait for you.
-Chris