On 28/06/16 17:56, Dave Gordon wrote:
Part spin-wait, part sleep-wait.
Plus one example of where it might be used.
Signed-off-by: Dave Gordon <david.s.gordon@xxxxxxxxx>
---
drivers/gpu/drm/i915/i915_guc_submission.c | 2 +-
drivers/gpu/drm/i915/intel_drv.h | 10 ++++++++++
2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c
index 355b647..ff99910 100644
--- a/drivers/gpu/drm/i915/i915_guc_submission.c
+++ b/drivers/gpu/drm/i915/i915_guc_submission.c
@@ -98,7 +98,7 @@ static int host2guc_action(struct intel_guc *guc, u32 *data, u32 len)
I915_WRITE(HOST2GUC_INTERRUPT, HOST2GUC_TRIGGER);
/* No HOST2GUC command should take longer than 10ms */
- ret = wait_for_atomic(host2guc_action_response(dev_priv, &status), 10);
+ ret = wait_for_hybrid(host2guc_action_response(dev_priv, &status), 10, 10);
if (status != GUC2HOST_STATUS_SUCCESS) {
/*
* Either the GuC explicitly returned an error (which
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 3156d8d..096e07c 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -103,6 +103,16 @@
#define wait_for_atomic(COND, MS) _wait_for_atomic((COND), (MS) * 1000)
#define wait_for_atomic_us(COND, US) _wait_for_atomic((COND), (US))
+/* Hybrid wait:
+ * first spin-wait for up to <US> microseconds,
+ * if <COND> still not true, sleep-wait for MS milliseconds
+ */
+#define wait_for_hybrid(COND, US, MS) ({ \
+ int ret__ = wait_for_atomic_us(COND, US); \
+ if (ret__) ret__ = wait_for(COND, MS); \
+ ret__; \
+ })
+
#define KHz(x) (1000 * (x))
#define MHz(x) KHz(1000 * (x))
Wouldn't harm anything if you know typical GuC response time is under
10us and 10ms timeout is backed with some documentation.
Another idea could be a wait_for variant which takes those values, so
typical and maximum response time, and then it could decide statically
in the macro what to do.
Regards,
Tvrtko
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