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?
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