From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Belmonte Subject: Re: powernow-k8 and stuck change-pending bit Date: Tue, 26 Jul 2005 00:34:14 -0400 Message-ID: <42E5BD46.4000806@neggie.net> References: <84EA05E2CA77634C82730353CBE3A843028F4CC5@SAUSEXMB1.amd.com> <42CFDF41.3040504@neggie.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <42CFDF41.3040504@neggie.net> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: cpufreq-bounces@lists.linux.org.uk Errors-To: cpufreq-bounces+glkc-cpufreq=m.gmane.org@lists.linux.org.uk Content-Type: text/plain; charset="us-ascii" Cc: cpufreq@lists.linux.org.uk John Belmonte wrote: > Devriendt, Paul wrote: > >>>symptoms: >>> >>> After working fine for a while (several minutes to several hours), >>>cpufreq seems to get into a bad state where: >>> >>> * change pending bit set / stuck kernel messages appear >>> >>> * reloading powernow-k8 module fails, with "change >>>pending bit stuck" >> > [...] > >>The most likely scenario here is the VRM was unable to change >>voltage, and that means flaky hardware as it has previously been >>able to successfully do so. The reason I pick on the VRM and not >>some sort of issue with the HyperTransport fabric is that it is >>unlikely anything would still be alive if there was some sort of >>problem coming back from the LDT_STOP. >> >>Assuming the VRM continues to supply the current voltage within >>spec, the system will stay up indefinitely, at the current >>voltage and frequency. >> >>The best path to follow would be to investigate warrantee replacement >>of the board. > > > Thanks for the info Paul. I've had the motherboard replaced with an > identical model. This new board seems to have the same problem, except > that when a transition finally fails, Linux hangs bad enough to require > a hard reset of the system. > > With two boards having this problem, it suggests either a bad > motherboard design or some bad interaction between Linux and the > motherboard. (It seems strange that the manufacturer wouldn't have seen > this problem under Windows.) Much less likely is that I have a bad CPU. An update to this story: I've replaced my motherboard with a different brand and model (DFI K8M800-MLVF) and am encountering the same power throttling issue. It does share the same Via chipset as my previous motherboard. I guess the next stop on this arduous trek is to try a different chipset. --John