From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: Crash on reading the whole PCI config of PIIX4 SMBus Date: Wed, 23 Sep 2009 16:15:18 +0200 Message-ID: <20090923161518.5cb29107@hyperion.delvare> References: <4AB8F142.9090609@nachtwindheim.de> <20090922231839.GA20656@pengutronix.de> <4ABA1B9C.9070302@nachtwindheim.de> <20090923153531.1642b77d@hyperion.delvare> <4ABA2CA1.8070806@nachtwindheim.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4ABA2CA1.8070806-lmEOmhgwvqJeCmjzdEDfrw@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Henrik Kretzschmar Cc: Wolfram Sang , jbarnes-Y1mF5jBUw70BENJcbMCuUQ@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org On Wed, 23 Sep 2009 16:11:45 +0200, Henrik Kretzschmar wrote: > Jean Delvare schrieb: > > You might still want to check if maybe ACPI is interfering with the > > i2c-piix4 driver. This isn't the kind of result I'd expect, but who > > knows. > > > This machine doesnt even have ACPI. :) Just APM. > > But reading the config space may be dangerous, refering the manpage of lspci: > " > -xxx Show hexadecimal dump of the whole PCI configuration space. It > is available only to root as several PCI devices crash when you > try to read some parts of the config space (this behavior proba- > bly doesnt violate the PCI standard, but its at least very > stupid). However, such devices are rare, so you neednt worry > much. > " > > I seem to have stumbled over one of those stupidnesses. > That is the reason why non-root users are only allowed to > read the first 64 byte of the config space. That's right, but it doesn't explain why i2c-piix4 crashes in the first place, not why merely loading it causes further lspci -xxx to crash when they did not beforehand. I admit I am totally clueless. > > So its imho generally a good idea to run lspci -xxx on every machine you can > and save some time searching in the wrong places. -- Jean Delvare