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Message-ID: <4ADEDBFD.6030305@sbg.ac.at> Date: Wed, 21 Oct 2009 12:01:33 +0200 From: Alexander Huemer <alexander.huemer@....ac.at> To: Jean Delvare <jdelvare@...e.de> CC: Tejun Heo <tj@...nel.org>, Frans Pop <elendil@...net.nl>, linux-kernel@...r.kernel.org, linux-ide@...r.kernel.org, Jeff Garzik <jgarzik@...ox.com>, alexander.huemer@....ac.at Subject: Re: 2.6.{30,31} x86_64 ahci problem - irq 23: nobody cared Jean Delvare wrote: > Hi Tejun, Alexander, > > Le mardi 13 octobre 2009, Tejun Heo a écrit : > >> Alexander Huemer wrote: >> >>> i compiled gcc in a loop over night, 14 times. no error. >>> it really seams i2c_i801 was the cause... >>> unfortunately i still don't know how i can extract the part of the gcc >>> compilation process that causes the error on an affected kernel. >>> that would enable me to create a simple test program. >>> >> Given that i2c is used for temperature monitoring, I think it is not >> triggered by any single step of the compiling but rather by the >> accumulated heat load during compilation. Let's wait for Jean to >> chime in. :-) >> > > OK, here I am, sorry for the delay. I've read the discussion thread. > Here are the few data points I can offer, in the hope it will help: > > * While the i2c-i801 driver received some changes in kernel 2.6.30, > none of these are related to PCI nor interrupts. So as the problem > is new in kernel 2.6.30, the i2c-i801 driver alone is unlikely to > cause it. This may, however, be a combination of something i2c-i801 > does and something the pci subsystem does since kernel 2.6.30. For > this reason, I would still recommend a bisection if the problem can > be reliably reproduced. I know it takes time, but it is always > easier to fix a bug when we know which commit introduced it. > > * The i2c-i801 driver does _not_ make use of interrupts. It is > poll-based (I am not exactly proud of that, but that's the way it > is.) > > #define ENABLE_INT9 0 /* set to 0x01 to enable - untested */ > > So I am very surprised to read that this driver would cause an IRQ > storm. > > * One thing the i2c-i801 driver does on the PCI device is: > > err = pci_enable_device(dev); > > I presume this is what causes the following message in dmesg: > > i801_smbus 0000:00:1f.3: PCI INT B -> GSI 23 (level, low) -> IRQ 23 > > Basically, even though the driver doesn't make use of interrupts, > the IRQ is still registered because this is how the hardware is > setup. > > As a conclusion, I suspect that 2 things may be happening: either > the SMBus is triggering interrupts when told not to. The ICH6 is a > bit different from all the other supported chips, I'll double check > if we may have missed something. Or, something else is triggering > SMBus transactions. SMI and ACPI come to mind. If this is the case > then you do not want to use i2c-i801 on this motherboard. > > Questions to Alexander : > > * Can I please see the output of "sensors" on your system? > * What are the brand and model of your motherboard? > * Can we get an acpidump for your system? > > many thanks for your response. i appreciate that. first, the data you requested: sensors: http://xx.vu/~ahuemer/sensors-ahuemer-20091021.txt acpidump: http://xx.vu/~ahuemer/acpidump-ahuemer-20091021.txt motherboard: tyan tempest i5400pw/s5397 with one intel xeon e5420. the output of sensors was made _without_ i801_smbus in the kernel. i noticed that the data of w83627hf-isa-0290 is quite weird. i do not have an explanation for that. if a bisection is what will bring light into this, i am willing to take the time. so that would be a bisection between 2.6.29 and 2.6.30 ? a quicker test case would be good for that, but i don't have one yet, just the compilation of gcc, which takes time, even on this machine with tmpfs and ccache. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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