| Message ID | 20221003170849.383005-1-echanude@redhat.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | mailbox: qcom-ipcc: flag IRQ NO_THREAD | expand |
On 2022-10-03 13:08:49 [-0400], Eric Chanudet wrote: > PREEMPT_RT forces qcom-ipcc's handler to be threaded with interrupts > enabled, which triggers a warning in __handle_irq_event_percpu(): > irq 173 handler irq_default_primary_handler+0x0/0x10 enabled interrupts > WARNING: CPU: 0 PID: 77 at kernel/irq/handle.c:161 __handle_irq_event_percpu+0x4c4/0x4d0 > > Mark it IRQF_NO_THREAD to avoid running the handler in a threaded > context with threadirqs or PREEMPT_RT enabled. The important bit of information is that this is a IRQ-multiplexer and such it must not be threaded. Otherwise its child-interrupts would be invoked from the thread handler which is not desired. This is noticed by PREEMPT_RT but also on a non-PREEMPT_RT kernel where `threadirqs' has been used. Side note: Using request_irq() has the side effect that this interrupt pops-up in /proc/interrupts and the "child-interrupt", too. So you account two interrupts while "one" on the HW side occurred. Maybe irq_set_chained_handler_and_data() would be better use. Either way, this addresses the problem, Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > Signed-off-by: Eric Chanudet <echanude@redhat.com> Sebastian
On Tue, Oct 04, 2022 at 11:41:50AM +0200, Sebastian Andrzej Siewior wrote: > On 2022-10-03 13:08:49 [-0400], Eric Chanudet wrote: > > PREEMPT_RT forces qcom-ipcc's handler to be threaded with interrupts > > enabled, which triggers a warning in __handle_irq_event_percpu(): > > irq 173 handler irq_default_primary_handler+0x0/0x10 enabled interrupts > > WARNING: CPU: 0 PID: 77 at kernel/irq/handle.c:161 __handle_irq_event_percpu+0x4c4/0x4d0 > > > > Mark it IRQF_NO_THREAD to avoid running the handler in a threaded > > context with threadirqs or PREEMPT_RT enabled. > > The important bit of information is that this is a IRQ-multiplexer and > such it must not be threaded. Otherwise its child-interrupts would be > invoked from the thread handler which is not desired. > This is noticed by PREEMPT_RT but also on a non-PREEMPT_RT kernel where > `threadirqs' has been used. Thank you, I will send a v2 shortly updating the description with the above. > Side note: Using request_irq() has the side effect that this interrupt > pops-up in /proc/interrupts and the "child-interrupt", too. So you > account two interrupts while "one" on the HW side occurred. > Maybe irq_set_chained_handler_and_data() would be better use. I see. > Either way, this addresses the problem,
diff --git a/drivers/mailbox/qcom-ipcc.c b/drivers/mailbox/qcom-ipcc.c index 31d58b7d55fe..7e27acf6c0cc 100644 --- a/drivers/mailbox/qcom-ipcc.c +++ b/drivers/mailbox/qcom-ipcc.c @@ -308,7 +308,8 @@ static int qcom_ipcc_probe(struct platform_device *pdev) goto err_mbox; ret = devm_request_irq(&pdev->dev, ipcc->irq, qcom_ipcc_irq_fn, - IRQF_TRIGGER_HIGH | IRQF_NO_SUSPEND, name, ipcc); + IRQF_TRIGGER_HIGH | IRQF_NO_SUSPEND | + IRQF_NO_THREAD, name, ipcc); if (ret < 0) { dev_err(&pdev->dev, "Failed to register the irq: %d\n", ret); goto err_req_irq;
PREEMPT_RT forces qcom-ipcc's handler to be threaded with interrupts enabled, which triggers a warning in __handle_irq_event_percpu(): irq 173 handler irq_default_primary_handler+0x0/0x10 enabled interrupts WARNING: CPU: 0 PID: 77 at kernel/irq/handle.c:161 __handle_irq_event_percpu+0x4c4/0x4d0 Mark it IRQF_NO_THREAD to avoid running the handler in a threaded context with threadirqs or PREEMPT_RT enabled. Signed-off-by: Eric Chanudet <echanude@redhat.com> --- drivers/mailbox/qcom-ipcc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)