linux-kernel - Re: [RFC][PATCH] PM: Print a warning if firmware is requested when tasks are frozen

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Date:	Mon, 02 May 2011 19:30:12 -0400
From:	Valdis.Kletnieks@...edu
To:	"Rafael J. Wysocki" <rjw@...k.pl>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Linux PM mailing list <linux-pm@...ts.linux-foundation.org>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [RFC][PATCH] PM: Print a warning if firmware is requested when tasks are frozen

On Tue, 03 May 2011 00:44:51 +0200, "Rafael J. Wysocki" said:

> +	if (WARN_ON(usermodehelper_is_disabled()))
> +		return -EBUSY;
> +

Since this is a "no user serviceable parts inside" type of error, so I guess
WARN_ON rather than a printk(KERN_WARNING is a good idea so we get
a traceback pointing out the offending driver.

I have to wonder 2 things though:

1) What percent of the time the missing firmware (or other issues, like the
display not being resumed yet) will prevent the WARN_ON output from making it
to the display *anyhow*, so the user *still* hits the power button to try again?

2) What percent of the time the WARN_ON output will itself make the user
think the resume has died rather than just being slow, causing them to power
cycle and hope for a clean boot?

Maybe something like this instead?

	if (WARN_ON(usermodehelper_is_disable()))) {
		printk(KERN_WARNING "Resume continuing, but firmware for %s not loaded", device);
		return -EBUSY;
	}

(or whatever that %s actually needs to work)

All the same, it still looks better than what we're doing now.

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