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Dedicated wakeirq is a one time event to wake-up the system from
low-power state and then call pm_runtime_resume() on the device wired
with the dedicated wakeirq.
Sometimes dedicated wakeirqs can get deferred if they trigger after we
call disable_irq_nosync() in dev_pm_disable_wake_irq(). This can happen
if pm_runtime_get() is called around the same time a wakeirq fires.
If an interrupt fires after disable_irq_nosync(), by default it will get
tagged with IRQS_PENDING and will run later on when the interrupt is
enabled again.
Deferred wakeirqs usually just produce pointless wake-up events. But they
can also cause suspend to fail if the deferred wakeirq fires during
dpm_suspend_noirq() for example. So we really don't want to see the
deferred wakeirqs triggering after the device has resumed.
Let's fix the issue by setting IRQ_DISABLE_UNLAZY flag for the dedicated
wakeirqs. The other option would be to implement irq_disable() in the
dedicated wakeirq controller, but that's not a generic solution.
For reference below is what happens with a IRQ_TYPE_EDGE_BOTH IRQ
type wakeirq:
- resume by dedicated IRQ (EDGE_FALLING)
- suspend_enter()
....
- arch_suspend_enable_irqs()
|- dedicated IRQ armed and fired
|- irq_pm_check_wakeup()
|- disarm, disable IRQ and mark as IRQS_PENDING
....
- dpm_resume_noirq()
|- resume_device_irqs()
|- __enable_irq()
|- check_irq_resend()
|- handle_threaded_wake_irq()
|- dedicated IRQ processed
|- device_wakeup_disarm_wake_irqs()
|- disable_irq_wake()
....
!-> dedicated IRQ (EDGE_RISING)
-| handle_edge_irq()
|- IRQ disabled: mask_ack_irq and mark as IRQS_PENDING
....
- subsequent suspend
....
|- dpm_suspend_noirq()
|- device_wakeup_arm_wake_irqs()
|- __enable_irq()
|- check_irq_resend()
(a) |- handle_threaded_wake_irq()
|- pm_wakeup_event() --> abort suspend
....
|- suspend_device_irqs()
|- suspend_device_irq()
|- dedicated IRQ armed
....
(b) |- resend_irqs
|- irq_pm_check_wakeup()
|- IRQ armed -> abort suspend
because of pending IRQ System suspend can be aborted at points
(a)-not armed or (b)-armed.
Fixes:
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|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.