linux/drivers/gpu/drm/i915/Kconfig.unstable
Matthew Auld 1629224324 drm/i915/lmem: add the fake lmem region
Intended for upstream testing so that we can still exercise the LMEM
plumbing and !i915_ggtt_has_aperture paths. Smoke tested on Skull Canyon
device. This works by allocating an intel_memory_region for a reserved
portion of system memory, which we treat like LMEM. For the LMEMBAR we
steal the aperture and 1:1 it map to the stolen region.

To enable simply set the i915 modparam fake_lmem_start= on the kernel
cmdline with the start of reserved region(see memmap=). The size of the
region we can use is determined by the size of the mappable aperture, so
the size of reserved region should be >= mappable_end. For now we only
enable for the selftests. Depends on CONFIG_DRM_I915_UNSTABLE being
enabled.

eg. memmap=2G$16G i915.fake_lmem_start=0x400000000

v2: make fake_lmem_start an i915 modparam

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Cc: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191030173320.8850-1-matthew.auld@intel.com
2019-10-31 20:41:47 +00:00

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# SPDX-License-Identifier: GPL-2.0-only
config DRM_I915_UNSTABLE
bool "Enable unstable API for early prototype development"
depends on EXPERT
depends on STAGING
depends on BROKEN # should never be enabled by distros!
# We use the dependency on !COMPILE_TEST to not be enabled in
# allmodconfig or allyesconfig configurations
depends on !COMPILE_TEST
default n
help
Enable prototype uAPI under general discussion before they are
finalized. Such prototypes may be withdrawn or substantially
changed before release. They are only enabled here so that a wide
number of interested parties (userspace driver developers) can
verify that the uAPI meet their expectations. These uAPI should
never be used in production.
Recommended for driver developers _only_.
If in the slightest bit of doubt, say "N".
config DRM_I915_UNSTABLE_FAKE_LMEM
bool "Enable the experimental fake lmem"
depends on DRM_I915_UNSTABLE
default n
help
Convert some system memory into a fake local memory region for
testing.