On Thu, 23 Mar 2017, Lionel DEBIEVE wrote:
> On 03/22/2017 07:47 PM, Julia Cartwright wrote:
> > On Wed, Mar 22, 2017 at 01:30:12PM -0500, Grygorii Strashko wrote:
> >> On 03/22/2017 01:01 PM, Steven Rostedt wrote:
> >>> On Wed, 22 Mar 2017 12:37:59 -0500
> >>> Julia Cartwright <julia@xxxxxx> wrote:
> >>>
> >>>> Which kernel were you testing on, here? From what I can tell, this
> >>>> should have been fixed with Thomas's commit:
> >>>>
> >>>> 2a1d3ab8986d ("genirq: Handle force threading of irqs with primary
> >>>> and thread handler")
> >>> Thanks Julia for looking into this. I just looked at the code, and saw
> >>> that it does very little with the lock held, and was fine with the
> >>> conversion. But if that interrupt handler should be in a thread, we
> >>> should see if that's the issue first.
> >>
> >> It will not be threaded because there are IRQF_ONESHOT used.
> >>
> >> ret = devm_request_threaded_irq(&pdev->dev, irq,
> >> sti_mbox_irq_handler,
> >> sti_mbox_thread_handler,
> >> IRQF_ONESHOT, mdev->name, mdev);
> > Indeed. I had skipped over this important detail when I was skimming
> > through the code.
> >
> > Thanks for clarifying!
> >
> > Is IRQF_ONESHOT really necessary for this device? The primary handler
> > invokes sti_mbox_disable_channel() on the interrupting channel, which I
> > would hope would acquiesce the pending interrupt at the device-level?
Not sure. This part of the code is remanent from when I re-wrote it.
What is the alternative?
NB: What does 'acquiesce' mean in this context? Is that a typo?
> > Also, as written there are num_inst reads of STI_IRQ_VAL_OFFSET in the
> > primary handler, which seems inefficient...(unless of course reading
> > incurs side effects, here).
Inefficient in what respect?
> First to reply Julia, test was made using 4.9.y kernel branch.
> For the IRQF_ONESHOT, I rely on Lee (adding in mail thread) that was at the device driver origin.
>
> Steven, you're also right as the patch can be also pushed in mainline too.
>
> Lionel
>
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Lee Jones
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