drm/i915: Remove redundant TLB invalidate on switching contexts
authorChris Wilson <chris@chris-wilson.co.uk>
Mon, 27 Feb 2017 13:59:11 +0000 (13:59 +0000)
committerChris Wilson <chris@chris-wilson.co.uk>
Mon, 27 Feb 2017 16:01:45 +0000 (16:01 +0000)
commit20fe17aa52dcafd3bdeb9e37281d027b0c1c5a15
tree1f7ffffb437a3622b1a28faa0bb9d9a29221d8be
parent6067a27d1f0184596d51decbac1c1fdc4acb012f
drm/i915: Remove redundant TLB invalidate on switching contexts

We are required to reload the TLBs around context switches
(MI_SET_CONTEXT specifically) and the recommendation is do that before
the MI_SET_CONTEXT so that it is serialised with the switch and not
forgotten:

[DevSNB] If Flush TLB invalidation Mode is enabled it’s the driver’s
responsibility to invalidate the TLBs at least once after the previous
context switch after any GTT mappings changed (including new GTT entries).
This can be done by a pipeline PIPE_CONTROL with TLB inv bit set
immediately before MI_SET_CONTEXT.

However, we already do an unconditional TLB invalidate before every
batch so this condition is satifisfied.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170227135913.8056-1-chris@chris-wilson.co.uk
drivers/gpu/drm/i915/i915_gem_context.c