Re: [PATCH v5 1/3] dt-bindings: net: wireless: add flag marvell,ignore-regulatory-hint

George Valkov <[email protected]>
Newsgroups org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel,org.kernel.vger.linux-wireless,org.kernel.vger.stable
Message-ID <CADOrJmZpJo+MDZpaAC=cGv-i_ZZ0wNjWsMP-dttnE3aQPpHLMA@mail.gmail.com>
On Tue, 18 Aug 2026 at 03:53, Andrew Lunn <[email protected]> wrote:
>
> > +  marvell,ignore-regulatory-hint:
> > +    $ref: /schemas/types.yaml#/definitions/flag
> > +    description:
> > +      Ignore an incorrect regulatory hint from ROM,
> > +      so userspace can set the correct regulatory domain.
> > +
>
> Maybe this has been discussed in a previous version of this patch...
>
> What is Marvell specific here? I assume any vendor can mess up, and
> make a US only device, but ship it elsewhere.

I don't recall any previous discussion on that topic, other than the
use of a root flag in v3, which was objected to, because
marvell,ignore-regulatory-hint does not belong there. I assume this is
due to the marvell prefix. I guess we can have a generic flag?
Implementation instructions, along with good design patterns are
warmly welcomed.

I like the idea of implementing a standardised approach, which is
scalable to any platform or driver that needs this quirk. I would also
like to add this feature to mwlwifi (not part of Linux), because the
main radios (88W8964) on WRT3200ACM have a hard-coded region of 98
(non-standard EU, translated to FR because it's the most restrictive).
This way I can set my correct region: BG.

In theory it is possible for other vendors to make the same mess. I
think the chances are very low, because they would violate
regulations. The story with this Linksys router is special:
It was designed and marketed to be OpenWrt compatible. Likely because
open-source gives a lot of power they made sure the hands of all users
are well tied-up: all radios use proprietary firmware and are
locked-down to their certified region in ROM. They do not allow
anything related to regions to be set. A third radio 88W8887 using the
mwifiex driver was added with the sole purpose to monitor for radars:
this idea was later abandoned. I do not have any information about
this choice, but my educated guess is that using a US radio created a
conflict and they disabled support for this radio to avoid it.

openwrt-ai:
https://github.com/openwrt/openwrt/pull/24458#pullrequestreview-4956971863
TLDR: It suggests that the compatible string should be marvell,sd8887
instead of marvell,sd8897. The string it suggested is not documented
and would need more changes, which I hope to avoid. I prefer keeping
things simple. The string I used works and is documented.

Sashiko-bot complained that patch 2 adds a flag to the device-tree,
with no support in the driver. Patch 3 adds support in the driver. Let
me know if I should reorder them?

Greetings!

Georgi Valkov
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