Re: watchdog: iTCO_wdt: failed to load

From: Guenter Roeck <linux@roeck-us.net>
To: Vignesh Raman <vignesh.raman.in@gmail.com>,
	linux-watchdog@vger.kernel.org
Cc: andriy.shevchenko@linux.intel.com, rajneesh.bhardwaj@linux.intel.com
Subject: Re: watchdog: iTCO_wdt: failed to load
Date: Wed, 24 Jul 2019 06:27:03 -0700	[thread overview]
Message-ID: <97817286-92ae-cd13-4cc1-7a0355140414@roeck-us.net> (raw)
In-Reply-To: <CAH3OF53GqY-h+9woZS_8Kx671PCiCFjVbaFQ_gs30ZXMWxUO8g@mail.gmail.com>

On 7/24/19 12:34 AM, Vignesh Raman wrote:
> Hi,
> 
> I'm seeing an issue where the iTCO_wdt module doesn't load with the below error,
> 
> [    3.827599] iTCO_wdt: Intel TCO WatchDog Timer Driver v1.11
> [    3.828440] iTCO_wdt iTCO_wdt: can't request region for resource
> [mem 0x00c5fffc-0x00c5ffff]
> [    3.828803] iTCO_wdt: probe of iTCO_wdt failed with error -16
> 
> CPU and logs:
> cpu: Intel(R) Core(TM) i3-8100 CPU @ 3.60GHz
> dmesg logs: http://paste.debian.net/1092702/
> lsmod output: https://paste.debian.net/1092703/
> root@localhost:~# uname -a
> Linux localhost.localdomain 4.14.103-rt55 #1 SMP PREEMPT RT Tue Jul 23
> 03:53:28 UTC 2019 x86_64 GNU/Linux
> 
> Please let me know if the error (can't request region for resource) is
> related to the patches below,
> https://patchwork.kernel.org/patch/9627085/
> https://lore.kernel.org/patchwork/patch/770990/
> 
> I tested with the patch
> https://lore.kernel.org/patchwork/patch/770990/ and it fixes the
> issue.
> root@localhost:/home/vignesh# dmesg | grep wdt
> [    5.766470] iTCO_wdt: Intel TCO WatchDog Timer Driver v1.11
> [    5.767104] iTCO_wdt: Found a Intel PCH TCO device (Version=4,
> TCOBASE=0x0400)
> [    5.767865] iTCO_wdt: initialized. heartbeat=30 sec (nowayout=0)
> 
> But the patch was not merged upstream.
> 
> When testing the hardware watchdog, it doesn't trigger a reset even
> after triggering a sysrq crash.
> The system freezes and there is no reboot.
> 
> I noticed the timeleft value is not getting updated.
> root@localhost:~# cat /sys/class/watchdog/watchdog0/timeleft
> 15
> root@localhost:~# cat /sys/class/watchdog/watchdog0/timeleft
> 15
> root@localhost:~# cat /sys/class/watchdog/watchdog0/timeleft
> 15
> 
> This issue has been discussed in below email thread,
> http://lkml.iu.edu/hypermail/linux/kernel/1609.1/01979.html
> https://lkml.org/lkml/2016/9/8/641
> 
> In another platform the hardware watchdog works.
> root@debian:~# dmesg | grep wdt
> [    3.901842] iTCO_wdt: Intel TCO WatchDog Timer Driver v1.11
> [    3.903415] iTCO_wdt: Found a Intel PCH TCO device (Version=4,
> TCOBASE=0x0400)
> [    3.937816] iTCO_wdt: initialized. heartbeat=30 sec (nowayout=0)
> 
> CPU and logs
> cpu: Intel(R) Core(TM) i7-6700 CPU @ 3.40GHz
> dmesg logs: http://paste.debian.net/1092845/
> lsmod output: http://paste.debian.net/1092846/
> root@debian:~# uname -a
> Linux debian 4.14.103-rt55 #1 SMP PREEMPT RT Tue Jul 23 03:53:28 UTC
> 2019 x86_64 GNU/Linux
> 
> Hardware watchdog triggers a reset and the watchdog timer counter is
> started and the value gets updated.
> root@debian:~# cat /sys/class/watchdog/watchdog0/timeleft
> 13
> root@debian:~# cat /sys/class/watchdog/watchdog0/timeleft
> 12
> root@debian:~# cat /sys/class/watchdog/watchdog0/timeleft
> 11
> root@debian:~#
> 
> My questions:
> 1. Please let me know if it is okay to take
> https://lore.kernel.org/patchwork/patch/770990/ patch or will there be
> an update to the original patch?
> 2. Could the hardware watchdog not triggering a reset (timeleft value
> not getting updated) could be a hardware problem?
> 

What is the output of /proc/iomem, what PCI devices does it have, and what are
the ACPI devices ? Reason for asking is that I don't immediately see the ACPI
or PCI devices associated with above patch in your dmesg. If not, the patch
might actually cause the watchdog in your system not to work.

Also, did this ever work in your system ? If it did work, did the failure
start after a kernel update or after a BIOS update ?

Thanks,
Guenter