Unblacklisting the ARM SBSA Watchdog driver

[Antoine Lassagne]

Hello kernel team,

I'm asking here about the possibility of removing the blacklist that is put
on the sbsa_gwdt module.
This module handles the ARM SBSA Generic watchdog [1]. The module kicks the
watchdog when it's there and, without it, some machines will get unattended
reboot after a few minutes of uptime.

All the watchdog modules were blacklisted a long time ago, after there were
problems with an HP watchdog if I understand it correctly. This comment
from Andy Whitcroft [2] is the closest related message I could find about
"why" this blacklist exists.

Now, some devices actually need this. Lately, Nvidia released ARM devices
that are based on an Ubuntu-based distro [3]. But if someone wants to
install stock Ubuntu on these, the hardware will reboot after 10min.

After I asked around, I came up with a hacky package that bypasses the
blacklist only on some identified hardware [4]. The problem is that it
requires us to identify the hardware first, and then it's hard-coded and
will not support new hardware without an update. Unblacklisting the
watchdog would be very, very much better, so much more hardware would be
supported.

Is there a path towards unblacklisting this specific watchdog on
resolute/devel, and get some user feedback?

[1]
https://www.kernel.org/doc/Documentation/devicetree/bindings/watchdog/sbsa-gwdt.txt

[2] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1432837/comments/3
[3] https://www.nvidia.com/en-us/products/workstations/dgx-spark/
[4] https://bugs.launchpad.net/ubuntu/+bug/2132001

Antoine

-- 
[image: Canonical Logo]

Antoine Lassagne

Senior Software Engineer

Email:

antoine.lassagne at canonical.com


Location:

France


canonical.com

ubuntu.com
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