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drm/i915: Stop second guessing the caller for intel_uncore_wait_for_register() 

Allow the caller to use the fast_timeout_us to specify how long to wait
within the atomic section, rather than transparently switching to a
sleeping loop for larger values. This is required as some callsites may
need a long wait and are in an atomic section.

v2: Reinforce kerneldoc fast_timeout_us limit with a GEM_BUG_ON

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170411112705.12656-1-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
This commit is contained in:
Chris Wilson 2017-04-11 12:27:05 +01:00
parent 6976e74b5f
commit 84d84cb7e2
1 changed files with 7 additions and 5 deletions
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12
drivers/gpu/drm/i915/intel_uncore.c
View File

@ -1601,7 +1601,7 @@ static int gen6_reset_engines(struct drm_i915_private *dev_priv,
*
* Otherwise, the wait will timeout after @slow_timeout_ms milliseconds.
* For atomic context @slow_timeout_ms must be zero and @fast_timeout_us
* must be not larger than 10 microseconds.
* must be not larger than 20,0000 microseconds.
*
* Note that this routine assumes the caller holds forcewake asserted, it is
* not suitable for very long waits. See intel_wait_for_register() if you
@ -1623,16 +1623,18 @@ int __intel_wait_for_register_fw(struct drm_i915_private *dev_priv,
int ret;
/* Catch any overuse of this function */
might_sleep_if(fast_timeout_us > 10 || slow_timeout_ms);
might_sleep_if(slow_timeout_ms);
GEM_BUG_ON(fast_timeout_us > 20000);
if (fast_timeout_us > 10)
ret = _wait_for(done, fast_timeout_us, 10);
else
ret = -ETIMEDOUT;
if (fast_timeout_us && fast_timeout_us <= 20000)
ret = _wait_for_atomic(done, fast_timeout_us, 0);
if (ret)
ret = wait_for(done, slow_timeout_ms);
if (out_value)
*out_value = reg_value;
return ret;
#undef done
}