I'd like to propose that we push the i915 suspend_late/resume_early code
into suspend_noirq/resume_noirq in order to reduce the total suspend time
by ~15ms. According to the comments, when i915_pm_suspend_late was first
added to the kernel back in April 2014, it was done so to ensure that it
was called after the snd_hda_intel driver had finished its suspend.
The comments in i915_drv.c are here:
/*
* We have a suspedn ordering issue with the snd-hda driver also
* requiring our device to be power up. Due to the lack of a
* parent/child relationship we currently solve this with an late
* suspend hook.
*
* FIXME: This should be solved with a special hdmi sink device or
* similar so that power domains can be employed.
*/
I believe we could achieve the same ordering by simply pushing it to
suspend/resume_noirq. Thus we can effectively eliminate the suspend_late
and resume_early phases altogether in most simple systems. Does anyone see
a problem with this?
analyzesuspend outputs for freeze/suspend/hibernate (WITHOUT PATCH):
https://01org.github.io/suspendresume/i915/freeze-160422-155931-ivybridge-dev-late/
https://01org.github.io/suspendresume/i915/suspend-160422-155735-ivybridge-dev-late/
https://01org.github.io/suspendresume/i915/hibernate-160422-163915-ivybridge-dev-late/
analyzesuspend outputs for freeze/suspend/hibernate (WITH PATCH):
https://01org.github.io/suspendresume/i915/freeze-160422-162811-ivybridge-dev-noirq/
https://01org.github.io/suspendresume/i915/suspend-160422-162700-ivybridge-dev-noirq/
https://01org.github.io/suspendresume/i915/hibernate-160422-162952-ivybridge-dev-noirq/
Signed-off-by: Todd Brandt <todd.e.brandt@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_drv.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 30798cb..759d93c 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -1628,8 +1628,8 @@ static const struct dev_pm_ops i915_pm_ops = {
* PMSG_RESUME]
*/
.suspend = i915_pm_suspend,
- .suspend_late = i915_pm_suspend_late,
- .resume_early = i915_pm_resume_early,
+ .suspend_noirq = i915_pm_suspend_late,
+ .resume_noirq = i915_pm_resume_early,
.resume = i915_pm_resume,
/*
@@ -1648,12 +1648,12 @@ static const struct dev_pm_ops i915_pm_ops = {
* hibernation image [PMSG_RESTORE]
*/
.freeze = i915_pm_suspend,
- .freeze_late = i915_pm_suspend_late,
- .thaw_early = i915_pm_resume_early,
+ .freeze_noirq = i915_pm_suspend_late,
+ .thaw_noirq = i915_pm_resume_early,
.thaw = i915_pm_resume,
.poweroff = i915_pm_suspend,
- .poweroff_late = i915_pm_poweroff_late,
- .restore_early = i915_pm_resume_early,
+ .poweroff_noirq = i915_pm_poweroff_late,
+ .restore_noirq = i915_pm_resume_early,
.restore = i915_pm_resume,
/* S0ix (via runtime suspend) event handlers */
--
2.1.4
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