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Date: Mon, 3 Aug 2009 13:52:29 -0700
From: "Darrick J. Wong" <djwong@us.ibm.com>
To: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>, Andrew Morton <akpm@linux-foundation.org>,
       linux-kernel <linux-kernel@vger.kernel.org>,
       lm-sensors <lm-sensors@lm-sensors.org>,
       linux-acpi <linux-acpi@vger.kernel.org>
Subject: Re: [PATCH 2/2] acpi_power_meter: hwmon driver for ACPI 4.0 power
	meters
Message-ID: <20090803205229.GB14694@plum>
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On Mon, Jul 27, 2009 at 02:45:55PM +0800, Zhang Rui wrote:
> Hi, Darrick,
> 
> great job. :)

Thanks.

> we should at least send a netlink event for an ACPI power meter
> notification, shouldn't we?

Yes, an event would be useful at the very least for when the system starts
capping, though unfortunately there doesn't seem to be a Notify event for when
capping ends.

> we should create the hwmon sysfs I/F for the hwmon device,
> i.e. add the hwmon attributes
> under /sys/devices/LINUXSYS:00/.../ACPI000D:00/hwmon0/
> rather than /sys/devices/LINUXSYS:00/.../ACPI000D:00/

Hee, this is a tricky matter.  The other hwmon drivers create sysfs attributes
under the sysfs object, not in a separate "hwmonX" object, and as I recall
libsensors reads symlinks under the device object to figure out which bus the
sensor device lives on.  If it can't figure that out, it ignores the hwmon
device.

> 	  if (acpi_disable)
> 		return -ENODEV;

Noted.

> plus, _PMD is not supported in this driver, right?
> I agree with Yakui that we can create some ACPI device sysfs attributes
> besides the hwmon ones. e.g. exporting devices measured by the current
> ACPI power meter device to user space.

I agree.

--D