On Tue, Jul 31, 2018 at 09:01:12AM +0100, Russell King - ARM Linux wrote:
> On Tue, Jul 31, 2018 at 12:50:21AM +0200, Thomas Gleixner wrote:
> > On Mon, 30 Jul 2018, Bjorn Helgaas 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@xxxxxxxxx>
> > > >
> > > > 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:
> > >
> > > tda998x_create()
> > > request_threaded_irq(client->irq, NULL, ..., irqd_get_trigger_type(), ...)
> > > (I can't tell what irqd_get_trigger_type() does)
> >
> > It reads the trigger type back from the irq chip (level/edge/polarity) but
> > does not return with the ONESHOT bit set.
>
> What tree are you (Bjorn) using there? Looking in my git history,
> request_threaded_irq() was added in January 2014, as:
>
> + irqf_trigger =
> + irqd_get_trigger_type(irq_get_irq_data(client->irq));
> + ret = request_threaded_irq(client->irq, NULL,
> + tda998x_irq_thread,
> + irqf_trigger | IRQF_ONESHOT,
> + "tda998x", priv);
>
> and updated more recently for the CEC support in ae81553c30ef
> ("drm/i2c: tda998x: allow interrupt to be shared") to be:
>
> - irqf_trigger =
> + irq_flags =
> irqd_get_trigger_type(irq_get_irq_data(client->irq));
> + irq_flags |= IRQF_SHARED | IRQF_ONESHOT;
> ret = request_threaded_irq(client->irq, NULL,
> - tda998x_irq_thread,
> - irqf_trigger | IRQF_ONESHOT,
> + tda998x_irq_thread, irq_flags,
> "tda998x", priv);
>
> In all cases, IRQF_ONESHOT has been set for this threaded interrupt.
>
> I've also checked drm-next, and it doesn't show anything like what
> Bjorn quoted.
>
> Confused. Bjorn, can you double check that what you think are
> erroneous request_threaded_irq() calls are actually as per what
> you quoted please?
I was looking at v4.18-rc1, but in the case of tda998x_create(), I
overlooked this line:
irq_flags |= IRQF_SHARED | IRQF_ONESHOT;
Sorry!
