Regarding SMBus

Jan Kiszka jan.kiszka at
Wed Sep 9 10:02:10 CEST 2020

On 09.09.20 07:23, gopi ratnakaram via Xenomai wrote:
> Team,
> I am working with xenomai patched with kernel 4.19.59 on an Industrial
> motherboard which has an SMBus. After patching during my testing it was
> observed that the SMbus got some issues and the bus is locking immediately
> after running my application and the error log is as follows. But, when I
> run my SMbus based application in the kernel 4.15.0 without RT patching it
> was working fine. Is there any configuration setting while patching xenomai
> is causing this issue?
> --best regards,
> R Gopi Krishna,
> Svaya Robotics Pvt., Ltd.,
> Hyderabad, India.
> T: +91 40 2354 6019
> F: +91 40 2354 7901
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> -------------- next part --------------
> [    1.291726] i801_smbus 0000:00:1f.4: SPD Write Disable is set
> [    1.291801] i801_smbus 0000:00:1f.4: SMBus using PCI interrupt
> [  366.625686] i801_smbus 0000:00:1f.4: Timeout waiting for interrupt!

The Linux interrupt is not making it through. Is it shared with another
device that happens to be managed by an RTDM driver? Does the issue
disappear when keeping the kernel version, just turning of Xenomai and
I-pipe in the kernel configuration?


Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux

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