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From: Peter Hunt <peter.hunt@opengear.com>
To: netdev-bot+sashiko@kernel.org
Cc: loic.poulain@oss.qualcomm.com, Daniele Palmas <dnlplm@gmail.com>,
	ryazanov.s.a@gmail.com, johannes@sipsolutions.net,
	mani@kernel.org, andrew+netdev@lunn.ch, davem@davemloft.net,
	edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
	netdev@vger.kernel.org, mhi@lists.linux.dev,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next v9 2/2] net: wwan: mhi_wwan_ctrl: drive DTR/RTS via the IP_CTRL channel
Date: Tue, 13 Oct 2026 12:31:24 -0600	[thread overview]
Message-ID: <20261013183124.260511-1-peter.hunt@opengear.com> (raw)
In-Reply-To: <179191223098.434549.11899173102479904971@kernel.org>

Thanks for the review.

[Medium] a failed DTR/RTS send is not retried: agreed, and stress
testing confirmed it. With the change-only filter added in v9, rapidly
toggling DTR/RTS filled the IP_CTRL UL ring and updates were dropped
with -EAGAIN, so the modem could be left with a stale state. In v10
->dtr_rts only records the requested state and schedules a per-port
work item that sends the latest state, so a burst is coalesced into one
message, and a send that fails with -EAGAIN or -ENOMEM is retried with
whatever state is latest by then. The modem therefore ends up with the
final state requested.

[Low] sysfs unbind/rebind of mhi_wwan_dtr while an AT port is open:
agreed it's a root-only corner case. Reopening the port, or changing
DTR or RTS, sends the state again, so I've left it as is.

pw-bot: cr

      reply	other threads:[~2026-10-13 18:33 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-12 17:22 [PATCH net-next v9 0/2] net: wwan: support DTR/RTS on AT ports via MHI IP_CTRL Peter Hunt
2026-10-12 17:22 ` [PATCH net-next v9 1/2] net: wwan: core: propagate modem control signals to port drivers Peter Hunt
2026-10-13 17:23   ` netdev-bot+sashiko
2026-10-13 18:28     ` Peter Hunt
2026-10-12 17:22 ` [PATCH net-next v9 2/2] net: wwan: mhi_wwan_ctrl: drive DTR/RTS via the IP_CTRL channel Peter Hunt
2026-10-13 10:00   ` Loic Poulain
2026-10-13 17:23   ` netdev-bot+sashiko
2026-10-13 18:31     ` Peter Hunt [this message]

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