From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Belmonte Subject: Re: powernow-k8 and stuck change-pending bit Date: Sat, 09 Jul 2005 10:29:21 -0400 Message-ID: <42CFDF41.3040504@neggie.net> References: <84EA05E2CA77634C82730353CBE3A843028F4CC5@SAUSEXMB1.amd.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <84EA05E2CA77634C82730353CBE3A843028F4CC5@SAUSEXMB1.amd.com> 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" To: "Devriendt, Paul" Cc: cpufreq@lists.linux.org.uk 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. --John