[PATCH 02/26] drm/i915: Missed interrupt simulation is no more, tell the world

[Chris Wilson]

Using the guc, we cannot disable the user interrupt generation as we use
it for driving submission. And from Icelake, we no longer have the
ability to individually mask interrupt generation from each engine,
disabling our ability to fake missed interrupts.

In both cases, report back to userspace that the missed interrupt
generator is no longer available.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 23f38bc257a2..afe401c670a7 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -4097,6 +4097,17 @@ i915_ring_test_irq_set(void *data, u64 val)
 {
 	struct drm_i915_private *i915 = data;
 
+	/* GuC keeps the user interrupt permanently enabled for submission */
+	if (USES_GUC_SUBMISSION(i915))
+		return -ENODEV;
+
+	/*
+	 * From icl, we can no longer individually mask interrupt generation
+	 * from each engine.
+	 */
+	if (INTEL_GEN(i915) >= 11)
+		return -ENODEV;
+
 	val &= INTEL_INFO(i915)->ring_mask;
 	DRM_DEBUG_DRIVER("Masking interrupts on rings 0x%08llx\n", val);
 
-- 
2.18.0