drm/i915: Report to userspace if we have a (presumed) working GPU reset

In igt, we want to test handling of GPU hangs, both for recovery
purposes and for reporting. However, we don't want to inject a genuine
GPU hang onto a machine that cannot recover and so be permenantly
wedged. Rather than embed heuristics into igt, have the kernel report
exactly when it expects the GPU reset to work.

This can also be usefully extended in future to indicate different
levels of fine-grained resets.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Tim Gore <tim.gore@intel.com>
Cc: Tomas Elf <tomas.elf@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 22 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index a6d8a3ee7750..4a86cf007aa0 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1455,20 +1455,36 @@ static int gen6_do_reset(struct drm_device *dev)
 	return ret;
 }
 
-int intel_gpu_reset(struct drm_device *dev)
+static int (*intel_get_gpu_reset(struct drm_device *dev))(struct drm_device *)
 {
 	if (INTEL_INFO(dev)->gen >= 6)
-		return gen6_do_reset(dev);
+		return gen6_do_reset;
 	else if (IS_GEN5(dev))
-		return ironlake_do_reset(dev);
+		return ironlake_do_reset;
 	else if (IS_G4X(dev))
-		return g4x_do_reset(dev);
+		return g4x_do_reset;
 	else if (IS_G33(dev))
-		return g33_do_reset(dev);
+		return g33_do_reset;
 	else if (INTEL_INFO(dev)->gen >= 3)
-		return i915_do_reset(dev);
+		return i915_do_reset;
 	else
+		return NULL;
+}
+
+int intel_gpu_reset(struct drm_device *dev)
+{
+	int (*reset)(struct drm_device *);
+
+	reset = intel_get_gpu_reset(dev);
+	if (reset == NULL)
 		return -ENODEV;
+
+	return reset(dev);
+}
+
+bool intel_has_gpu_reset(struct drm_device *dev)
+{
+	return intel_get_gpu_reset(dev) != NULL;
 }
 
 void intel_uncore_check_errors(struct drm_device *dev)