Raspberry Pi 3 i2c timed out on Arch64 headless

[rontant]

I am running Arch64 headless on Raspberry Pi 3 and quite often dmesg gets flooded with i2c timed out lines. Usually a reboot would solve this but sometimes it takes two or three reboots to make it disappear. Am I the only one having this issue?

$this->bbcode_second_pass_code('', '[root@alarmpi ~]# uname -a
Linux alarmpi 4.11.6-1-ARCH #1 SMP Sat Jun 17 12:13:16 MDT 2017 aarch64 GNU/Linux')

[andre]

Can you post the messages you get on dmesg? Also, what is connected to the i²c bus?

[rontant]

Here it is:
$this->bbcode_second_pass_code('', '[root@alarmpi ~]# dmesg | tail
[ 11.911229] smsc95xx 1-1.1:1.0 eth0: hardware isn't capable of remote wakeup
[ 11.923505] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready
[ 12.051163] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
[ 12.808523] EXT4-fs (sda2): mounted filesystem with ordered data mode. Opts: (null)
[ 13.422972] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready
[ 13.441831] smsc95xx 1-1.1:1.0 eth0: link up, 100Mbps, full-duplex, lpa 0xC5E1
[ 74.526682] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
[ 106.526574] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
[ 118.046572] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
[ 129.566640] i2c-bcm2835 3f805000.i2c: i2c transfer timed out

[root@alarmpi ~]# dmesg | grep i2c
[ 8.376799] i2c-bcm2835 3f805000.i2c: Could not read clock-frequency property
[ 9.886661] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
[ 12.051163] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
[ 74.526682] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
[ 106.526574] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
[ 118.046572] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
[ 129.566640] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
[ 171.808367] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
[ 193.569415] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
[ 205.089877] i2c-bcm2835 3f805000.i2c: i2c transfer timed out
')
Nothing is connected to my Pi 3 i2c bus. Again, this doesn't happen every time but when it happens, dmesg will be flooded with these "i2c transfer timed out" messages continuously. The good thing is one or two reboots will make it go away.

[andre]

For some reason it is attempting to transfer something on the bus. If there is no device connected, obviously it will get a time out. So the question is what is it trying to communicate with?

Personally, I haven't tried running the 64 bit kernel op my raspberry pi 3 yet, but I suppose it uses the same bootloader, device tree and device tree overlays. Therefore I suggest looking at the /boot/config.txt file. Is there a line like
$this->bbcode_second_pass_code('', 'dtparam=i2c_arm=on')
then comment out that line, and any other lines that might invoke i2c.

[rontant]

/boot/config.txt only contains one line. Here it is:

$this->bbcode_second_pass_code('', '[root@alarmpi ~]# ls -al /boot
total 54384
drwxr-xr-x 3 root root 4096 Jan 1 1970 .
drwxr-xr-x 20 root root 4096 Jun 21 17:20 ..
-rwxr-xr-x 1 root root 20877824 Jun 18 02:18 Image
-rwxr-xr-x 1 root root 8398232 Jun 18 02:18 Image.gz
-rwxr-xr-x 1 root root 822 Jun 21 17:10 boot.scr
-rwxr-xr-x 1 root root 750 Jun 21 17:10 boot.txt
-rwxr-xr-x 1 root root 50216 Jun 14 10:28 bootcode.bin
-rwxr-xr-x 1 root root 14 Mar 22 10:05 config.txt
drwxr-xr-x 13 root root 4096 May 26 09:44 dtbs
-rwxr-xr-x 1 root root 6669 Jun 14 10:28 fixup.dat
-rwxr-xr-x 1 root root 2593 Jun 14 10:28 fixup_cd.dat
-rwxr-xr-x 1 root root 9804 Jun 14 10:28 fixup_db.dat
-rwxr-xr-x 1 root root 13500595 Jun 18 09:03 initramfs-linux-fallback.img
-rwxr-xr-x 1 root root 3901894 Jun 18 09:02 initramfs-linux.img
-rwxr-xr-x 1 root root 369312 Mar 22 10:05 kernel8.img
-rwxr-xr-x 1 root root 239 Mar 22 10:05 mkscr
-rwxr-xr-x 1 root root 2855972 Jun 14 10:28 start.elf
-rwxr-xr-x 1 root root 660036 Jun 14 10:28 start_cd.elf
-rwxr-xr-x 1 root root 4994308 Jun 14 10:28 start_db.elf

[root@alarmpi ~]# cat /boot/config.txt
enable_uart=1')