From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King Subject: cpufreq on ARM - 2.6 problem Date: Tue, 2 Sep 2003 18:21:59 +0100 Sender: cpufreq-bounces+glkc-cpufreq=gmane.org@www.linux.org.uk Message-ID: <20030902182158.C9345@flint.arm.linux.org.uk> Mime-Version: 1.0 Return-path: Content-Disposition: inline List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: cpufreq-bounces+glkc-cpufreq=gmane.org@www.linux.org.uk Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: cpufreq@www.linux.org.uk Hi, There seems to be a problem with cpufreq on SA11x0 platforms when resuming. The effect seems to be a hang. I suspect that this is caused by the cpufreq resume method being a sys device (and therefore called with interrupts off). It sets the CPU clock rate, which in turn calls the transition notifier, which might (and does) sleep. (of course, all this happens when the serial console is disabled because its a device not a sysdevice, so getting debug out of the system is nigh on impossible.) I'm not sure what the right way to handle this is, and still ensure that all drivers have the right settings for stuff like SDRAM and LCD timings. I'm also concerned that the backport of 2.6 stuff to 2.4 may introduce the same problem into 2.4 kernels. -- Russell King (rmk@arm.linux.org.uk) The developer of ARM Linux http://www.arm.linux.org.uk/personal/aboutme.html