From mboxrd@z Thu Jan 1 00:00:00 1970 From: Russell King Subject: Re: cpufreq/linux/arch/arm/mach-sa1100 cpu-sa1100.c, 1.5, Date: Mon, 30 Aug 2004 15:29:54 +0100 Sender: cpufreq-bounces@www.linux.org.uk Message-ID: <20040830152954.A22480@flint.arm.linux.org.uk> References: <20040829124936.GA16770@dominikbrodowski.de> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <20040829124936.GA16770@dominikbrodowski.de>; from linux@dominikbrodowski.de on Sun, Aug 29, 2004 at 02:49:36PM +0200 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 On Sun, Aug 29, 2004 at 02:49:36PM +0200, Dominik Brodowski wrote: > With regard to PANIC_RESUME_OUTOFSYNC: > > > It's up to the kernel to reset the clock rate itself. This is nothing > > new - cpufreq has always done this, so why are we adding this new > > restriction? > > cpufreq still does this. However not during sysdev-resume state [because > notifiers can sleep], but later. This means the problematic discrepancy (see > above) is there, just for a short period of time. If you think it isn't an > issue, Bruno's patch to remove both flags is perfectly valid, otherwise > these flags do make some sense. Typically, the boot loader will have a fixed clock speed and RAM timing setting. This means that whenever we resume, we will resume not at the speed the kernel last set, but what we normally boot at. If we normally boot at 206.4MHz, we will resume at 206.4MHz no matter what. So, with PANIC_RESUME_OUTOFSYNC that seems to mean that we will _always_ panic on resume if cpufreq has been used. Which kind'a makes cpufreq completely useless on these platforms. Obviously given this information, this flag needs to be removed from ARM. If ARM is the only user, then the flag and associated code needs to be completely removed. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 PCMCIA - http://pcmcia.arm.linux.org.uk/ 2.6 Serial core