linux-kernel - Re: [PATCH] gpio: omap: Fix double trigger for level interrupts

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Message-ID: <6ecd284a-e3f5-4b69-b6d7-129da6b385c1@moroto.mountain>
Date: Tue, 26 Mar 2024 18:29:45 +0300
From: Dan Carpenter <dan.carpenter@...aro.org>
To: Markus Schneider-Pargmann <msp@...libre.com>
Cc: Grygorii Strashko <grygorii.strashko@...com>,
	Santosh Shilimkar <ssantosh@...nel.org>,
	Kevin Hilman <khilman@...nel.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Bartosz Golaszewski <brgl@...ev.pl>, linux-omap@...r.kernel.org,
	linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
	Markus Mirevik <markus.mirevik@...olutions.se>
Subject: Re: [PATCH] gpio: omap: Fix double trigger for level interrupts

In the bug report email thread Markus Mirevik said "The interrupt
associated with the GPIO module still fires twice" so while this patch
is an improvement, it might not be a complete solution?

> This patch was originally proposed by Grygorii Strashko.

The way to give authorship credit is you make the first line of your
patch:

From: Grygorii Strashko <grygorii.strashko@...com>

When the patch is applied then git will assign authorship credit but
remove that line from the git log.

On Tue, Mar 26, 2024 at 03:50:14PM +0100, Markus Schneider-Pargmann wrote:
> Set gpio trigger before clearing the irq status.
> 

This commit message needs some work.  When you're reviewing on email,
it's kind of common to read the commit message without reading the
subject.  See how the patch looks like on lore:

https://lore.kernel.org/linux-gpio/20240326145439.1293412-1-msp@baylibre.com/T/#u

The subject is up on the first line, but it's mixed in with the headers
so it's easy to skip.  Go ahead a restate the subject but in different
words.

But also copy and paste more of the problem from the bug report.  To me
if I were a user the important bit is that the bug ends up hogging the
CPU.

"The problem is that the interrupt handler was is run twice for each
frame.  It hogs a lot of CPU time.  Fix this by setting the GPIO trigger
before clearing the IRQ status."

regards,
dan carpenter