On Fri, Jan 20, 2012 at 11:09:29PM +0200, Pasi Kärkkäinen wrote:
On Thu, Jan 19, 2012 at 02:53:17PM -0600, Seth Forshee wrote:
On Thu, Jan 19, 2012 at 02:48:52PM -0500, Alex Deucher wrote:
On Thu, Jan 19, 2012 at 12:18 PM, Seth Forshee seth.forshee@canonical.com wrote:
I'm seeing several issues related to the radeon driver on a MacBook Pro 8,2 with the following graphics card:
ATI Technologies Inc Whistler [AMD Radeon HD 6600M Series] [1002:6741]
All problems were observed when using kernel version 3.2.1. None are seen when using fglrx.
1. Excessive power draw. When using the radeon driver ACPI reports a power draw of about 30W on an idle desktop. Using fglrx brings this number down to 15W.
The power saving features of the open source driver are not yet as good as the closed source driver. Please see the power management section of this page (http://wiki.x.org/wiki/RadeonFeature) for more info on the options currently available.
The dynpm option makes a small difference, saving about 2W. I did notice an ocassional flash on the screen with this option, and the same flash each time I changed the power options.
Btw how do you measure the power draw?
You can get the instantaneous rate from the data under /proc/acpi/battery, but I use a tool called powerstat [1], written by my colleague Colin King. The advantage of powerstat is that it samples the ACPI data over a period of time and reports the average and standard deviation. That way I have a better idea of how much power is really being drawn and the quality of the value reported.