Unblacklisting the ARM SBSA Watchdog driver

[Antoine Lassagne]

Hi Paolo,

Thank you, that's great news. A few follow-up questions:
- Is there a way for me to test this already? Maybe I can simply build the
unstable branch locally?
- When is 6.19 due in resolute/linux?
I'll run some verifications on it, and will also try to get it verified
against more arm64 machines. Thank you again.

Antoine

On Wed, 21 Jan 2026 at 17:16, Paolo Pisati <paolo.pisati at canonical.com>
wrote:

> On Thu, Jan 15, 2026 at 4:04 PM Antoine Lassagne <
> antoine.lassagne at canonical.com> wrote:
>
>> 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?
>>
>
> Hi Antoine,
> your request makes sense: i pushed a patch on top of linux-unstable [1]
> that removes sbsa_gwdt from the watchdog blacklist - it will appear in
> resolute/linux once it moves to v6.19.
>
> 1:
> https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/unstable
> --
> bye,
> p.
>
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