From: Sean Wang <sean.wang@kernel.org>
To: Javier Tia <floss@jetm.me>
Cc: Bradley Pizzimenti <brad.pizzimenti@gmail.com>,
linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org,
nbd@nbd.name, lorenzo@kernel.org, ryder.lee@mediatek.com,
shayne.chen@mediatek.com, sean.wang@mediatek.com,
"moderated list:ARM/Mediatek SoC support"
<linux-mediatek@lists.infradead.org>
Subject: Re: [bug report] wifi: mt76: mt7925: iw set txpower fixed accepted but ignored
Date: Wed, 6 May 2026 19:11:53 -0500 [thread overview]
Message-ID: <CAGp9LzqkJ8QoOnBAiGu=uum3-LmCB3yHr91sw1HoLw+7ewNx6A@mail.gmail.com> (raw)
In-Reply-To: <20260506200918.D68321EA006C@mailuser.phl.internal>
Hi,
The TX power reporting issue has already been investigated by Lucid
from the Linux WiFi USB community, and there is a proposed solution.
I think we can continue checking whether there are any remaining
issues on top of that work. Please refer to the patches here:
https://lists.infradead.org/pipermail/linux-mediatek/2026-April/105726.html
Thanks everyone for reporting and raising these concerns.
On Wed, May 6, 2026 at 3:09 PM Javier Tia <floss@jetm.me> wrote:
>
> On Sun May 4 22:04:48 2026 Bradley Pizzimenti wrote:
> > `iw dev <iface> set txpower fixed N` returns success on mt7925 for
> > any N tested, but the reported txpower never changes from a stuck
> > value of 3.00 dBm.
>
> Hi Bradley,
>
> The 3 dBm display bug is a known issue we have seen when using mt7927
> and a tested fix has been working well so far. The root cause is that
> mt7925_mcu_set_rate_txpower() programs the per-band SKU tables into
> firmware but never assigns phy->txpower_cur. mt76_get_txpower() then
> computes:
>
> DIV_ROUND_UP(0 + 6, 2) = 3
>
> regardless of the actual power level. The RF output is unaffected;
> it is a display-only bug.
>
> The fix reads the effective TX power back from the rate power limits
> after programming the SKU tables and writes it to phy->txpower_cur,
> following the same pattern used by mt7996:
>
> https://github.com/jetm/mediatek-mt7927-dkms/blob/master/mt7927-wifi-14-fix-reported-txpower-always-showing-3-db.patch
>
> This is part of a series we are targeting for wireless-next; not
> yet upstream.
>
> > What seems potentially distinct here is that the user-issued
> > `iw set txpower fixed N` itself is silently no-op'd, separate
> > from the reported-value question.
>
> Agreed those are two separate issues. Our patch addresses the
> display-only side: after applying it, iw will report the value the
> firmware is actually using based on the SKU tables, rather than
> always 3 dBm. Whether `set txpower fixed N` propagates to firmware
> to change actual output power is orthogonal and not addressed here.
>
> If you can test the patch on your MT7925 and confirm the displayed
> value reflects the correct power after association, a Tested-by
> would be appreciated.
>
> Best,
> Javier
>
next parent reply other threads:[~2026-05-07 0:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CACjnFagN9zeSkwEv3-CSPJDUENPcEcOLjKyQoLQ91Yjn=rq5ww@mail.gmail.com>
[not found] ` <20260506200918.D68321EA006C@mailuser.phl.internal>
2026-05-07 0:11 ` Sean Wang [this message]
2026-05-07 0:27 ` [bug report] wifi: mt76: mt7925: iw set txpower fixed accepted but ignored John Henry
2026-05-11 17:58 ` John Henry
2026-05-17 13:01 ` John Henry
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CAGp9LzqkJ8QoOnBAiGu=uum3-LmCB3yHr91sw1HoLw+7ewNx6A@mail.gmail.com' \
--to=sean.wang@kernel.org \
--cc=brad.pizzimenti@gmail.com \
--cc=floss@jetm.me \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mediatek@lists.infradead.org \
--cc=linux-wireless@vger.kernel.org \
--cc=lorenzo@kernel.org \
--cc=nbd@nbd.name \
--cc=ryder.lee@mediatek.com \
--cc=sean.wang@mediatek.com \
--cc=shayne.chen@mediatek.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).