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 18:30:29 +0200 Message-ID: <20090923183029.4f0e8ac5@hyperion.delvare> References: <4AB8F142.9090609@nachtwindheim.de> <20090922231839.GA20656@pengutronix.de> <4ABA1B9C.9070302@nachtwindheim.de> <20090923153531.1642b77d@hyperion.delvare> <4ABA2CA1.8070806@nachtwindheim.de> <20090923161518.5cb29107@hyperion.delvare> <4ABA4382.1000707@nachtwindheim.de> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4ABA4382.1000707@nachtwindheim.de> Sender: linux-pci-owner@vger.kernel.org To: Henrik Kretzschmar Cc: Wolfram Sang , linux-pci@vger.kernel.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-i2c@vger.kernel.org On Wed, 23 Sep 2009 17:49:22 +0200, Henrik Kretzschmar wrote: > Jean Delvare schrieb: > > > 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. > > > Sorry, I expressed myself a bit unclear. > > With _worked_ I meant the system crashed (thats what killer commands are for). > > lspci -xxx (and co) bring this system down in every case, module loaded or not. > Obvious this crash occuress when reading the config space in short periods. Ah, OK, thanks for the clarification. > lspci (or better proc-fs and sys-fs) do that, and i2c-piix4 does it sometimes. > > Looking at read() of drivers/pci/proc.c i had the idea of stalking the critical area with: > > #!/bin/sh > for i in `seq 100`; do > dd if=/proc/bus/pci/00/07.3 of=/dev/null bs=1 count=n 2>/dev/null; > done > > > I got no crashes with n == 192, but with n == 193 theres no reaction from the system. > > Maybe it's interesting, that (all the time after crashes) the screen > (in my case the console with a blinking cursor) can still be seen. > But no reaction on keyboard hits. I think it is typical of IRQ routing gone out to lunch. > Also strange is, that the device works well IF those two read accesses have not done the crash. > I'll test tomorrow without the second read access, just to know if it works. -- Jean Delvare