Thread (12 messages) 12 messages, 4 authors, 2020-03-23

Re: [PATCH v3 2/2] pinctrl: stm32: Add level interrupt support to gpio irq chip

From: Marc Zyngier <maz@kernel.org>
Date: 2020-03-23 19:25:24
Also in: linux-gpio, lkml

On Mon, 23 Mar 2020 20:04:23 +0100
Marek Vasut [off-list ref] wrote:
On 2/20/20 10:17 AM, Marc Zyngier wrote:
quoted
On 2020-02-20 09:04, Linus Walleij wrote:
quoted
On Wed, Feb 19, 2020 at 3:32 PM Alexandre Torgue
[off-list ref] wrote:
quoted
GPIO hardware block is directly linked to EXTI block but EXTI handles
external interrupts only on edge. To be able to handle GPIO interrupt on
level a "hack" is done in gpio irq chip: parent interrupt (exti irq
chip)
is retriggered following interrupt type and gpio line value.

Signed-off-by: Alexandre Torgue <redacted>
Tested-by: Marek Vasut <marex@denx.de>
Reviewed-by: Linus Walleij <redacted>

If Marc want to merge it with patch 1/2 go ahead!
I'll queue the whole thing for 5.7.
I have a feeling this doesn't work with threaded interrupts.

If the interrupt handler runs in a thread context, the EOI will happen
almost right away (while the IRQ handler runs) and so will the code
handling the IRQ retriggering. But since the IRQ handler still runs and
didn't return yet, the retriggering doesn't cause the IRQ handler to be
called again once it finishes, even if the IRQ line is still asserted.
And that could result in some of the retriggers now happening I think.
Or am I doing something wrong ?
Wouldn't the hardirq handler mask the interrupt? This should certainly
be the case when IRQF_ONESHOT is set.

	M.
-- 
Jazz is not dead. It just smells funny...

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