linux-kernel - Re: [PATCH] Acer Aspire One Fan Control

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Message-ID: <20090426153100.GA7481@srcf.ucam.org>
Date:	Sun, 26 Apr 2009 16:31:01 +0100
From:	Matthew Garrett <mjg59@...f.ucam.org>
To:	Peter Feuerer <peter@...e.net>
Cc:	LKML <linux-kernel@...r.kernel.org>, lenb@...nel.org
Subject: Re: [PATCH] Acer Aspire One Fan Control

On Sat, Apr 25, 2009 at 10:42:51AM +0200, Peter Feuerer wrote:

Looks pretty good. Couple of minor questions:

> +	  The driver is started in "user" mode where the Bios takes care about
> +	  controlling the fan, unless a userspace program controls it.
> +	  To let the kernelmodule handle the fan, do:
> +	  echo kernel > /sys/class/thermal/thermal_zone0/mode
> +
> +	  For more information about this driver see
> +	  <http://piie.net/files/acerhdf_README.txt>

Maybe include the readme in Documentation/laptop?

> +/* if you want the module to be started in kernelmode,
> + * uncomment following line */
> +/* #define START_IN_KERNEL_MODE */

Maybe a module parameter?

> +/* set operation mode;
> + * kernel: a kernel thread takes care about managing the
> + *	 fan (see acerhdf_thread)
> + * user: kernel thread is stopped and a userspace tool
> + *	 should take care about managing the fan

This could be clearer. In user mode the fan will be controlled by the 
bios, right?

> +	/* silly hack - let the polling thread disable
> +	 * kernelmode. This ensures, that the polling thread
> +	 * doesn't switch off the fan again */

Is this still needed?

> +static int acerhdf_suspend(struct platform_device *dev,
> +		pm_message_t state)
> +{
> +	if (verbose)
> +		printk(KERN_NOTICE "acerhdf: going suspend\n");
> +	return 0;
> +}
> +
> +/* wake up */
> +static int acerhdf_resume(struct platform_device *device)
> +{
> +	if (verbose)
> +		printk(KERN_NOTICE "acerhdf: resuming\n");
> +	return 0;
> +}

Just remove these.

> +	/* print out bios data */
> +	printk(KERN_NOTICE "acerhdf: version: %s compilation date: %s %s\n",
> +			VERSION, __DATE__, __TIME__);
> +	printk(KERN_NOTICE "acerhdf: biosvendor:%s\n", vendor);
> +	printk(KERN_NOTICE "acerhdf: biosversion:%s\n", version);
> +	printk(KERN_NOTICE "acerhdf: biosrelease:%s\n", release);
> +	printk(KERN_NOTICE "acerhdf: biosproduct:%s\n", product);

Perhaps only do this if verbose mode is enabled? 5 lines of output for 
one driver seems excessive.

> +		printk(KERN_NOTICE
> +			"acerhdf: kernelmode disabled\n");
> +		printk(KERN_NOTICE
> +			"acerhdf: to enable kernelmode:\n");
> +		printk(KERN_NOTICE
> +			"acerhdf: echo -n \"enabled\" > "
> +			"/sys/class/thermal/thermal_zone0/mode\n");
> +		printk(KERN_NOTICE
> +			"acerhdf: for more information read:\n");
> +		printk(KERN_NOTICE
> +			"acerhdf: http://piie.net/files/acerhdf_README.txt\n");

This is the default behaviour, right? So that's another 5 lines by 
default. I don't think it's really necessary :)

I don't have an Aspire One to hand so can't test this, but otherwise it 
looks pretty good.

-- 
Matthew Garrett | mjg59@...f.ucam.org
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