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

From: Alex G.
Date: Wed Mar 20 2019 - 09:48:39 EST

On 3/20/19 8:46 AM, Bjorn Helgaas wrote:
Hi Alexandru,

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 <>

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.