linux_dsm_epyc7002/drivers/gpu/drm/i915/Kconfig.profile
Chris Wilson b27e35ae5b drm/i915: Keep user GGTT alive for a minimum of 250ms
Do not allow runtime pm autosuspend to remove userspace GGTT mmaps too
quickly. For example, igt sets the autosuspend delay to 0, and so we
immediately attempt to perform runtime suspend upon releasing the
wakeref. Unfortunately, that involves tearing down GGTT mmaps as they
require an active device.

Override the autosuspend for GGTT mmaps, by keeping the wakeref around
for 250ms after populating the PTE for a fresh mmap.

v2: Prefer refcount_t for its under/overflow error detection
v3: Flush the user runtime autosuspend prior to system system.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190527115114.13448-1-chris@chris-wilson.co.uk
2019-05-28 08:23:09 +01:00

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config DRM_I915_USERFAULT_AUTOSUSPEND
int "Runtime autosuspend delay for userspace GGTT mmaps (ms)"
default 250 # milliseconds
help
On runtime suspend, as we suspend the device, we have to revoke
userspace GGTT mmaps and force userspace to take a pagefault on
their next access. The revocation and subsequent recreation of
the GGTT mmap can be very slow and so we impose a small hysteris
that complements the runtime-pm autosuspend and provides a lower
floor on the autosuspend delay.
May be 0 to disable the extra delay and solely use the device level
runtime pm autosuspend delay tunable.
config DRM_I915_SPIN_REQUEST
int
default 5 # microseconds
help
Before sleeping waiting for a request (GPU operation) to complete,
we may spend some time polling for its completion. As the IRQ may
take a non-negligible time to setup, we do a short spin first to
check if the request will complete in the time it would have taken
us to enable the interrupt.
May be 0 to disable the initial spin. In practice, we estimate
the cost of enabling the interrupt (if currently disabled) to be
a few microseconds.