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From: Hayes Wang <hayeswang@realtek.com>
To: Douglas Anderson <dianders@chromium.org>,
        "David S . Miller"
	<davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>, Jakub Kicinski
	<kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
CC: "danielgeorgem@google.com" <danielgeorgem@google.com>,
        Andrew Lunn
	<andrew@lunn.ch>, Grant Grundler <grundler@chromium.org>,
        Heiner Kallweit
	<hkallweit1@gmail.com>,
        "linux-kernel@vger.kernel.org"
	<linux-kernel@vger.kernel.org>,
        "linux-usb@vger.kernel.org"
	<linux-usb@vger.kernel.org>,
        "netdev@vger.kernel.org"
	<netdev@vger.kernel.org>
Subject: RE: [PATCH REPOST net-next 1/2] r8152: If inaccessible at resume time, issue a reset
Thread-Topic: [PATCH REPOST net-next 1/2] r8152: If inaccessible at resume
 time, issue a reset
Thread-Index: AQHasuswBg+aoM1vbkGYnO9BBos/N7G1mwVQ
Date: Mon, 3 Jun 2024 06:39:02 +0000
Message-ID: <c885d8b6ade4442d9cacf36c55d81be5@realtek.com>
References: <66590f22.170a0220.8b5ad.1750@mx.google.com>
In-Reply-To: <66590f22.170a0220.8b5ad.1750@mx.google.com>
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Douglas Anderson <dianders@chromium.org>
> Sent: Friday, May 31, 2024 7:43 AM
[...]
> If we happened to get a USB transfer error during the transition to
> suspend then the usb_queue_reset_device() that r8152_control_msg()
> calls will get dropped on the floor. This is because
> usb_lock_device_for_reset() (which usb_queue_reset_device() uses)
> silently fails if it's called when a device is suspended or if too
> much time passes.
>=20
> Let's resolve this by resetting the device ourselves in r8152's
> resume() function.
>=20
> NOTE: due to timing, it's _possible_ that we could end up with two USB
> resets: the one queued previously and the one called from the resume()
> patch. This didn't happen in test cases I ran, though it's conceivably
> possible. We can't easily know if this happened since
> usb_queue_reset_device() can just silently drop the reset request. In
> any case, it's not expected that this is a problem since the two
> resets can't run at the same time (because of the device lock) and it
> should be OK to reset the device twice. If somehow the double-reset
> causes problems we could prevent resets from being queued up while
> suspend is running.
>=20
> Signed-off-by: Douglas Anderson <dianders@chromium.org>

Acked-by: Hayes Wang <hayeswang@realtek.com>

Best Regards,
Hayes