Re: [PATCH] PCI/LINK: bw_notification: Do not leave interrupt handler NULL

[Bjorn Helgaas]

On Wed, Mar 20, 2019 at 08:48:33AM -0500, Alex G. wrote:
> On 3/20/19 8:46 AM, Bjorn Helgaas wrote:
> > On Mon, Mar 18, 2019 at 08:12:04PM -0500, Alexandru Gagniuc wrote:
> > > A threaded IRQ with a NULL handler does not work with level-triggered
> > > interrupts. request_threaded_irq() will return an error:
> > > 
> > >    genirq: Threaded irq requested with handler=NULL and !ONESHOT for irq 16
> > >    pcie_bw_notification: probe of 0000:00:1b.0:pcie010 failed with error -22
> > > 
> > > For level interrupts we need to silence the interrupt before exiting
> > > the IRQ handler, so just clear the PCI_EXP_LNKSTA_LBMS bit there.
> > > 
> > > Reported-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> > > Signed-off-by: Alexandru Gagniuc <mr.nuke.me@xxxxxxxxx>
> > 
> > What's your thought regarding Lukas' comment?  If you do repost this,
> > please add a Fixes: tag to help connect this with the initial commit.
> 
> I like Lukas's idea. I should have this re-posted by end of week, unless
> there's an urgency to get it out earlier.

It would have been ideal to get the fix in -rc2, but I guess the end
of the week is OK because it's probably already too late for me to
apply it, run it through 0-day, get it in -next, and ask Linus to pull
it for -rc2.

Bjorn