linux-kernel - Re: [PATCH 3/4] PNP: Allow device to override ACPI device sleep

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Message-ID: <545AA139.9040207@hurleysoftware.com>
Date:	Wed, 05 Nov 2014 17:14:17 -0500
From:	Peter Hurley <peter@...leysoftware.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
CC:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
	Jiri Slaby <jslaby@...e.cz>
Subject: Re: [PATCH 3/4] PNP: Allow device to override ACPI device sleep

On 11/05/2014 05:28 PM, Rafael J. Wysocki wrote:
> On Wednesday, November 05, 2014 01:40:53 PM Peter Hurley wrote:
>> If the serial console is an ACPI PNP device, the PNP bus attempts to
>> power-down the device, even though the no_console_suspend command line
>> parameter is specified (eg., debugging suspend/resume).
>>
>> Add PNP_SUSPEND capability which is on by default, but when cleared,
>> prevents pnpacpi_suspend() (which is the ACPI PNP protocol ->suspend()
>> method).
>>
>> Signed-off-by: Peter Hurley <peter@...leysoftware.com>
> 
> While I'm not disagreeing with this entirely, I have a concern.
> 
> There are two types of suspend in Linux these days, runtime suspend and
> system suspend.  What this is about is "device suspend during system
> suspend" only, so the flag name is somewhat confusing.

Yeah, I see your point. I wouldn't want people thinking this had anything
to do with runtime pm.

> Also the flag is only going to be used for consoles, so why don't you
> introduce a PNP_CONSOLE flag and then define pnp_can_suspend() as
> 
> static inline pnp_can_suspend(struct pnp_dev *pnp_dev)
> {
> 	return pnp_dev->protocol->suspend &&
> 		 (!(pnp_dev->capabilities & PNP_CONSOLE) || console_suspend_enabled);
> }

I can do that.

Regards,
Peter Hurley
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