linux-kernel - Re: [v2] gpio: dwapb: mask/unmask IRQ when disable/enale it

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Date: Mon, 18 Dec 2023 13:33:05 +0200
From: Andy Shevchenko <andy@...nel.org>
To: xiongxin <xiongxin@...inos.cn>
Cc: fancer.lancer@...il.com, hoan@...amperecomputing.com,
	linus.walleij@...aro.org, brgl@...ev.pl, linux-gpio@...r.kernel.org,
	linux-kernel@...r.kernel.org, Riwen Lu <luriwen@...inos.cn>
Subject: Re: [v2] gpio: dwapb: mask/unmask IRQ when disable/enale it

On Mon, Dec 18, 2023 at 04:12:46PM +0800, xiongxin wrote:
> In the hardware implementation of the i2c hid driver based on dwapb gpio
> irq, when the user continues to use the i2c hid device in the suspend
> process, the i2c hid interrupt will be masked after the resume process
> is finished.
> 
> This is because the disable_irq()/enable_irq() of the dwapb gpio driver
> does not synchronize the irq mask register state. In normal use of the
> i2c hid procedure, the gpio irq irq_mask()/irq_unmask() functions are
> called in pairs. In case of an exception, i2c_hid_core_suspend() calls
> disable_irq() to disable the gpio irq. With low probability, this causes
> irq_unmask() to not be called, which causes the gpio irq to be masked
> and not unmasked in enable_irq(), raising an exception.
> 
> Add synchronization to the masked register state in the
> dwapb_irq_enable()/dwapb_irq_disable() function. mask the gpio irq
> before disabling it. After enabling the gpio irq, unmask the irq.

> Fixes: 7779b3455697 ("gpio: add a driver for the Synopsys DesignWare APB GPIO block")
> Signed-off-by: xiongxin <xiongxin@...inos.cn>

Your SoB should go last.

> Signed-off-by: Riwen Lu <luriwen@...inos.cn>

Then at all means what this SoB for? Either it's missing Co-developed-by,
or simply wrong.

> Tested-by: xiongxin <xiongxin@...inos.cn>

This is assumed to be done by the contributor, but it's harmless to have it.

With the above being sorted out,
Reviewed-by: Andy Shevchenko <andy@...nel.org>

...

To Serge, I give my vote to hwirq as it is aligned with the documentation.

-- 
With Best Regards,
Andy Shevchenko