On 09/06/2020 18:26, Tomi Valkeinen wrote:
On 09/06/2020 18:19, Tony Lindgren wrote:
But there's an extra runtime PM reference (dev.power.usage_count) that seems to come out of nowhere. So when omap_drm_suspend is finished, there's still usage_count of 1, and dispc never suspends fully.
Hmm no idea about that. My guess is that there might be an issue that was masked earlier with omap_device calling the child runtime_suspend.
Yes. It's how PM works. It calls pm_runtime_get_noresume() before starting the suspend of a device. So I guess omapdrm's suspend has been broken all the time, but it was "fixed" by omap_device.
I think I might have an idea what is going wrong.
Before: +----------------------+ |omap_device_pm_domain | +---------------+------+------+ | device | +-------------+ | omap_device | +-------------+
omap_device is embedded in DD device and PM handled by omap_device_pm_domain.
static int _od_suspend_noirq(struct device *dev) { ...
ret = pm_generic_suspend_noirq(dev); [1] ^^ device suspend_noirq call
if (!ret && !pm_runtime_status_suspended(dev)) { if (pm_generic_runtime_suspend(dev) == 0) { [2] ^^ device pm_runtime_suspend force call
omap_device_idle(pdev); [3] ^^ omap_device disable od->flags |= OMAP_DEVICE_SUSPENDED; } }
return ret; }
Now: +------------+ |ti sysc dev | +-+----------+ | | | +-------------+ | | device | +-->+ | +-------------+
With new approach the omap_device is not embedded in DD Device anymore, instead ti-sysc (hwmod replacement) became parent of DD Device.
As result suspend sequence became the following (Note. All PM runtime PUT calls became NOP during suspend by design):
device |-> suspend() - in case of dss omap_drm_suspend() and Co if defined |-> suspend_noirq() - in case of dss *not defined", equal to step [1] above ..
ti sysc dev (ti-sysc is parent, so called after device) |-> sysc_noirq_suspend |-> pm_runtime_force_suspend() |-> sysc_runtime_suspend() - equal to step [3] above
And step [2] is missing as of now!
I think, suspend might be fixed if all devices, which are now child of ti-sysc, will do pm_runtime_force_xxx() calls at noirq suspend stage by adding:
SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
Am I missing smth?