drm/i915/guc: Disable global reset
authorChris Wilson <chris@chris-wilson.co.uk>
Fri, 25 Jan 2019 13:22:27 +0000 (13:22 +0000)
committerChris Wilson <chris@chris-wilson.co.uk>
Fri, 25 Jan 2019 14:27:21 +0000 (14:27 +0000)
commitfe62365f9f80a1c1d438c54fba21f5108a182de8
treeaf83eeae22ab5a5dea2aa4af800c07bf70c75cff
parentade8a0f59844349650514f608eb1da5280f7818b
drm/i915/guc: Disable global reset

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@chris-wilson.co.uk>
Acked-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190125132230.22221-2-chris@chris-wilson.co.uk
drivers/gpu/drm/i915/i915_reset.c