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| author | Dave Gordon <david.s.gordon@intel.com> | 2016-07-06 16:30:11 +0200 |
|---|---|---|
| committer | Tvrtko Ursulin <tvrtko.ursulin@intel.com> | 2016-07-06 17:24:46 +0200 |
| commit | ab0e455bd0abe2b817c896b229b08045bafbdb94 (patch) | |
| tree | 58e6320508ae68872da490ecf7ff37df806cb362 /drivers/gpu | |
| parent | drm/i915: Group the irq breadcrumb variables into the same cacheline (diff) | |
| download | linux-ab0e455bd0abe2b817c896b229b08045bafbdb94.tar.xz linux-ab0e455bd0abe2b817c896b229b08045bafbdb94.zip | |
drm/i915: avoid wait_for_atomic() in non-atomic host2guc_action()
Rather than using wait_for_atomic() when chacking for a response from
the GuC, we can get the effect of a hybrid spin/sleep wait by breaking
it into two stages. First, spin-wait for up to 10us to minimise latency
for "quick" commands; then, if that times out, sleep-wait for up 10ms
(the maximum allowed for a "slow" command).
Being able to do this depends on the recent patch
18f4b84 drm/i915: Use atomic waits for short non-atomic ones
and is similar to the hybrid approach in
1758b90 drm/i915: Use a hybrid scheme for fast register waits
(although we can't use that as-is, because that interface doesn't quite
match what we need here).
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1467815411-21756-1-git-send-email-david.s.gordon@intel.com
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_guc_submission.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/i915_guc_submission.c b/drivers/gpu/drm/i915/i915_guc_submission.c index bfc8bf672f2d..2112e029db6a 100644 --- a/drivers/gpu/drm/i915/i915_guc_submission.c +++ b/drivers/gpu/drm/i915/i915_guc_submission.c @@ -97,8 +97,14 @@ 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); + /* + * Fast commands should complete in less than 10us, so sample quickly + * up to that length of time, then switch to a slower sleep-wait loop. + * No HOST2GUC command should ever take longer than 10ms. + */ + ret = wait_for_us(host2guc_action_response(dev_priv, &status), 10); + if (ret) + ret = wait_for(host2guc_action_response(dev_priv, &status), 10); if (status != GUC2HOST_STATUS_SUCCESS) { /* * Either the GuC explicitly returned an error (which |