On 11/04/2017 11:13, Chris Wilson wrote:
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.
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Michal Wajdeczko <michal.wajdeczko@xxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_uncore.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index eb38392a2435..53c8457869f6 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -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 +1623,17 @@ 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);
- if (fast_timeout_us > 10)
- ret = _wait_for(done, fast_timeout_us, 10);
- else
+ ret = -ETIMEDOUT;
+ if (fast_timeout_us && fast_timeout_us < 20000)
I agree with Michal here. Kerneldoc even says "must not be larger than
20ms" so it would be better and completely fine in my opinion to:
if (GEM_WARN_ON(fast_timeout_us > 20000))
return -EINVAL;
Hm but it would break the bisectability of the series and break the
sandybridge pcode.
So patch 4/5 looks broken since it changes the timeout from 500ms to
500us. I don't see how to fix that without splitting the _fw and atomic
concepts.
Regards,
Tvrtko
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
}
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