Re: [PATCH] PCI: let pci_request_irq properly deal with threaded interrupts

[Krzysztof Kozlowski <krzk@kernel.org>]

On 31 July 2018 at 00:42, Bjorn Helgaas <helgaas@kernel.org> wrote:
> [+cc maintainers of possibly erroneous callers of request_threaded_irq()]
>
> On Mon, Jul 30, 2018 at 04:30:28PM -0500, Bjorn Helgaas wrote:
>> [+cc Thomas, Christoph, LKML]
>>
>> On Mon, Jul 30, 2018 at 12:03:42AM +0200, Heiner Kallweit wrote:
>> > If we have a threaded interrupt with the handler being NULL, then
>> > request_threaded_irq() -> __setup_irq() will complain and bail out
>> > if the IRQF_ONESHOT flag isn't set. Therefore check for the handler
>> > being NULL and set IRQF_ONESHOT in this case.
>> >
>> > This change is needed to migrate the mei_me driver to
>> > pci_alloc_irq_vectors() and pci_request_irq().
>> >
>> > Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
>>
>> I'd like an ack from Thomas because this requirement about IRQF_ONESHOT
>> usage isn't mentioned in the request_threaded_irq() function doc or
>> Documentation/
>
> Possibly these other request_threaded_irq() callers are similarly
> broken?  I can't tell for sure about tda998x_create(), but all the
> others certainly call request_threaded_irq() with "handler == NULL"
> and irqflags that do not contain IRQF_ONESHOT:
>
>   max8997_muic_probe()
>     request_threaded_irq(virq, NULL, ..., IRQF_NO_SUSPEND, ...)
>
>   tda998x_create()
>     request_threaded_irq(client->irq, NULL, ..., irqd_get_trigger_type(), ...)
>     (I can't tell what irqd_get_trigger_type() does)
>
>   ab8500_btemp_probe()
>   ab8500_charger_probe()
>     request_threaded_irq(irq, NULL, ..., IRQF_SHARED | IRQF_NO_SUSPEND, ...)
>
>   lp8788_set_irqs()
>     request_threaded_irq(virq, NULL, ..., 0, ...)
>
>   max77686_rtc_probe()
>     request_threaded_irq(info->virq, NULL, ..., 0, ...)

max77686 works fine because it it is nested IRQ. Parent has ONESHOT flag set.

Best regards,
Krzysztof