linux-kernel - Re: [PATCH] ACPI / GED: unregister interrupts during shutdown

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Date:   Thu, 7 Dec 2017 09:52:06 -0500
From:   Sinan Kaya <okaya@...eaurora.org>
To:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     "Rafael J. Wysocki" <rafael@...nel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Timur Tabi <timur@...eaurora.org>,
        linux-arm-msm@...r.kernel.org,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ACPI / GED: unregister interrupts during shutdown

Rafael,

On 12/7/2017 8:00 AM, Rafael J. Wysocki wrote:
>> Just don't use devm_request_threaded_irq()?  :)
>>
>> Seriously, those are just "helper" functions if your code happens to
>> follow the pattern they provide, if not, then don't use them, it's not
>> that hard to provide the correct code to unwind things properly by "open
>> coding" this logic as needed.
>>
>> The devm_*irq() functions are known for not being able to be used all of
>> the time for lots of shutdown and cleanup issues, this isn't the first
>> time it has happened, which is why we are very careful when taking
>> "cleanup" patches that use those functions.
> I see, thanks for the clarification.
> 
> OK, we'll need to rework the driver somewhat, then.

Even if we got rid of devm_*irq() functions, I see that the free_irq() function
requires dev_id argument.

	 * There can be multiple actions per IRQ descriptor, find the right
	 * one based on the dev_id:

I still need to keep track of the dev_ids attached to request_irq() functions. 

My take away from the discussion is:
1. don't use devm family of functions for IRQ registration/free
2. still keep track of the events
3. call free_irq on shutdown.

Do you have something else on your mind?

Sinan

-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.