drm/i915: Restore context and pd for ringbuffer submission after reset

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Following a reset, the context and page directory registers are lost.
However, the queue of requests that we resubmit after the reset may
depend upon them - the registers are restored from a context image, but
that restore may be inhibited and may simply be absent from the request
if it was in the middle of a sequence using the same context. If we
prime the CCID/PD registers with the first request in the queue (even
for the hung request), we prevent invalid memory access for the
following requests (and continually hung engines).

v2: Magic BIT(8), reserved for future use but still appears unused.
v3: Some commentary on handling innocent vs guilty requests
v4: Add a wait for PD_BASE fetch. The reload appears to be instant on my
Ivybridge, but this bit probably exists for a reason.

Fixes: 821ed7df6e ("drm/i915: Update reset path to fix incomplete requests")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170207152437.4252-1-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>

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This commit is contained in:

Chris Wilson 2017-02-07 15:24:37 +00:00

parent 6248017ae5

commit c0dcb203fb

4 changed files with 81 additions and 17 deletions

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18

drivers/gpu/drm/i915/i915_gem.c

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6

drivers/gpu/drm/i915/i915_reg.h

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16

drivers/gpu/drm/i915/intel_lrc.c

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58

drivers/gpu/drm/i915/intel_ringbuffer.c

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