From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============5634263278858920268==" MIME-Version: 1.0 From: Marc MERLIN Subject: Re: [Powertop] USB devices get wrong power use values Date: Sun, 13 Oct 2013 09:22:12 -0700 Message-ID: <20131013162212.GH30504@merlins.org> In-Reply-To: 525ABD5F.6030001@linux.intel.com To: powertop@lists.01.org List-ID: --===============5634263278858920268== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Sun, Oct 13, 2013 at 08:33:51AM -0700, Arjan van de Ven wrote: > On 9/22/2013 4:54 PM, Marc MERLIN wrote: > >So, I asked on the linux-usb list, and one thing I quickly found out is = that the > >Watt value given by powertop 2.4 is way off for USB devices: > = > what makes you think the value is off? > = > >>Power est. Events/s Category Description > >> 8.18 W 100.0% Device USB device: Yubico Yubikey II (= Yubico) > >> 8.13 W 100.0% Device USB device: Integrated Camera (= Chicony Electronics Co., Ltd.) > = > having a USB device active also generally makes the CPU/etc use much more= power, > which Powertop "charges" to the USB device in question. > = > 8 Watts sounds entirely reasonable for that to me... Aah, if the CPU gets involved, then yes, it's a bit more possible. So, a simple USB keyboard that's unused can keep one core awake and burn 8 watts if something else goes wrong in the kernel to cause that? Thanks, Marc -- = "A mouse is a device used to point at the xterm you want to type in" - A.S.= R. Microsoft is to operating systems .... .... what McDonalds is to gourmet coo= king Home page: http://marc.merlins.org/ | PGP 1024R/763= BE901 --===============5634263278858920268==--