[Intel-gfx] [RFC PATCH 14/42] drm/i915: introduce kernel blitter_context

[Chris Wilson]

Quoting Matthew Auld (2019-02-14 14:57:12)
> We may be without a context to perform various internal blitter
> operations, for example when performing object migration. Piggybacking
> off the kernel_context is probably a bad idea, since it has other uses.

Explain why it is a worse idea than creating yet another kernel context
to manage. The fact that we may use it for blitting makes the kernel
context even more viable for its other jobs (such as knowing we've
flushed off user contexts). Convince me that we really need more than
one internal context; and that blitting especially needs its own.
-Chris