Bug 206733

Summary: i2c i2c-3: i2c-powermac: modalias failure on /uni-n@f8000000/i2c@f8001000/cereal@1c0
Product: Platform Specific/Hardware Reporter: Erhard F. (erhard_f)
Component: PPC-32Assignee: platform_ppc-32
Status: NEW ---    
Severity: normal CC: andreas.thalhammer, benh, mathieu.malaterre, newchief
Priority: P1    
Hardware: PPC-32   
OS: Linux   
Kernel Version: 5.6-rc4 Subsystem:
Regression: No Bisected commit-id:
Attachments: dmesg (5.6-rc4, PowerMac G4 DP)
kernel .config (5.6-rc4, PowerMac G4 DP)

Description Erhard F. 2020-03-02 16:50:35 UTC
Created attachment 287759 [details]
dmesg (5.6-rc4, PowerMac G4 DP)

The G4 MDD/DP can't quite pick up this device, despite it shows up in the bootlog earlier.

[...]
Mär 02 17:23:45 T600 kernel: i2c-dev: adapter [uni-n 1] registered as minor 3
Mär 02 17:23:45 T600 kernel: i2c i2c-3: adapter [uni-n 1] registered
Mär 02 17:23:45 T600 kernel: PowerMac i2c bus uni-n 1 registered
Mär 02 17:23:45 T600 kernel: i2c i2c-3: i2c-powermac: register /uni-n@f8000000/i2c@f8001000/cereal@1c0
Mär 02 17:23:45 T600 kernel: i2c i2c-3: i2c-powermac: modalias failure on /uni-n@f8000000/i2c@f8001000/cereal@1c0
Mär 02 17:23:45 T600 kernel: i2c-dev: adapter [uni-n 0] registered as minor 4
[...]
Comment 1 Erhard F. 2020-03-02 16:58:23 UTC
Created attachment 287761 [details]
kernel .config (5.6-rc4, PowerMac G4 DP)
Comment 2 Mathieu Malaterre 2020-03-03 07:32:00 UTC
>  i2c i2c-3: i2c-powermac: modalias failure on
>  /uni-n@f8000000/i2c@f8001000/cereal@1c0

Ben,

Can you confirm this warning is harmless ?
Comment 3 Benjamin Herrenschmidt 2020-03-05 03:42:44 UTC
Yes. I had a look (and had to swap in some historical brain cells from tape storage :-) But I think the warning should probably be turned into a dev_dbg. It's probably some gunk in the device-tree but those "cereal" nodes don't matter (I don't remember what they represent but it's not something we care about).
Comment 4 Paul Osmialowski 2021-05-17 09:24:01 UTC
I've just updated to 5.10.27-gentoo on some old iBook G4, and of course I've spotted this `i2c-powermac: modalias failure on /uni-n@f8000000/i2c@f8001000/cereal@1c0` message. It is not worrying now after I've found Ben's comment. I've also spotted one more error message (Flag mismatch) that seems new to me, can you also make a judgement if it is also harmless?:

[...]
[    4.515861] hid-generic 0003:17EF:602E.0001: input,hidraw0: USB HID v1.11 Mouse [USB Optical Mouse] on usb-0001:10:1b.0-1/input0
[    4.660923] input: PowerMac Beep as /devices/pci0001:10/0001:10:17.0/input/input3
[    4.665549] genirq: Flags mismatch irq 21. 00000001 (i2sbus: i2s-a (tx)) vs. 00000001 (PMac Output)
[...]