From mboxrd@z Thu Jan 1 00:00:00 1970 From: andy@warmcat.com (Andy Green) Date: Thu, 11 Mar 2010 21:21:37 +0000 Subject: bit errors on spitz In-Reply-To: <1268322155.3990.114.camel@hammer.suse.cz> References: <20100305212708.GC21773@elf.ucw.cz> <20100308072858.GA29939@atrey.karlin.mff.cuni.cz> <20100308082530.GA1982@atrey.karlin.mff.cuni.cz> <4B98EF5D.5000609@warmcat.com> <1268322155.3990.114.camel@hammer.suse.cz> Message-ID: <4B995EE1.1050609@warmcat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 03/11/10 15:42, Somebody in the thread at some point said: > Andy Green wrote: > >> I saw very similar failures for a long time on our iMX31 based device. >> Eventually I found a Freescale errata where the RAM inside the USB2 >> macrocell started to make single bit errors below 1.38V Vcore; ours was >> 1.4V at that time but dipped on CPU load. > > Good tip. It seems that nobody ported driver for the voltage control > chip ISL6271 from 2.4 kernel, and bootloader probably does not set > correct values. > > Datasheet: > http://www.penguin.cz/~utx/zaurus/datasheets/power/Xscale/ISL6271.pdf Unless there's more to it in the way the zaurus using it that regulator isn't programmable digitally. Reading about your CF Card WLAN related issues they suck down a good amount of power when their radio is up, I would definitely suggest monitoring with a 'scope the various rails (Vcore, RAM and whatever it is the CF Card is powered by) while putting it under load. -Andy