drm/i915/execlists: Reset CSB write pointer after reset

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On HW reset, the HW clears the write pointer (to 0). But since it also
writes its first CSB entry to slot 0, we need to reset the write pointer
back to the element before (so the first entry we read is 0).

This is required for the next patch, where we trust the CSB completely!

v2: Use _MASKED_FIELD
v3: Store the reset value, so that we differentiate between mmio/hwsp
transparently and without pretense.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180628201211.13837-6-chris@chris-wilson.co.uk

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This commit is contained in:

Chris Wilson 2018-06-28 21:12:08 +01:00

parent bc4237ec8d

commit f4b58f0438

2 changed files with 30 additions and 2 deletions

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23

drivers/gpu/drm/i915/intel_lrc.c

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9

drivers/gpu/drm/i915/intel_ringbuffer.h

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