[Intel-gfx] [PATCH 09/34] drm/i915/guc: Disable global reset

[Chris Wilson]

The guc (and huc) currently inexcruitably depend on struct_mutex for
device reinitialisation from inside the reset, and indeed taking any
mutex here is verboten (as we must be able to reset from underneath any
of our mutexes). That makes recovering the guc unviable without, for
example, reserving contiguous vma space and pages for it to use.

The plan to re-enable global reset for the GuC centres around reusing the
WOPM reserved space at the top of the aperture (that we know we can
populate a contiguous range large enough to dma xfer the fw image).

In the meantime, hopefully no one even notices as the device-reset is
only used as a backup to the per-engine resets for handling GPU hangs.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Acked-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>
Acked-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
---
 drivers/gpu/drm/i915/i915_reset.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reset.c b/drivers/gpu/drm/i915/i915_reset.c
index b9d0ea70361c..2961c21d9420 100644
--- a/drivers/gpu/drm/i915/i915_reset.c
+++ b/drivers/gpu/drm/i915/i915_reset.c
@@ -590,6 +590,9 @@ int intel_gpu_reset(struct drm_i915_private *i915, unsigned int engine_mask)
 
 bool intel_has_gpu_reset(struct drm_i915_private *i915)
 {
+	if (USES_GUC(i915))
+		return false;
+
 	return intel_get_gpu_reset(i915);
 }
 
-- 
2.20.1