From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3C476C2B.80306@ixiacom.com> Date: Thu, 17 Jan 2002 16:28:27 -0800 From: Bryan Rittmeyer MIME-Version: 1.0 To: linuxppc-embedded@lists.linuxppc.org Subject: ppc750 TAU problems? Content-Type: text/plain; charset=us-ascii; format=flowed Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: Hello all, From Configure.help in a recent linuxppc_devel_2_4 snapshot (2.4.17): CONFIG_TAU G3 and G4 processors have an on-chip temperature sensor called the 'Thermal Assist Unit (TAU)', which, in theory, can measure the on-die temperature within 2-4 degrees Celsius. This option shows the current on-die temperature in /proc/cpuinfo if the cpu supports it. Unfortunately, on some chip revisions, this sensor is very inaccurate and in some cases, does not work at all, so don't assume the cpu temp is actually what /proc/cpuinfo says it is. Can anyone provide further details on which IBM PPC750CXe versions have problematic TAU? It seems our 400 MHz parts work great with this driver (25 to 30C when idle) but our 600 MHz grades always read out an incorrect range of "11-13 C" or even "1-71 C" while at room temperature. Increasing the sampling delay in temp.c has no effect. -Bryan -- Bryan Rittmeyer mailto:bryan@ixiacom.com ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/