From: Sven Peter <sven@kernel.org>
To: Janne Grunau <j@jannau.net>, Neal Gompa <neal@gompa.dev>,
Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: asahi@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH] usb: dwc3: apple: Ignore USB role switches to the active role
Date: Tue, 13 Jan 2026 07:58:56 +0100 [thread overview]
Message-ID: <675f32d7-c866-4b66-93bb-0dc6ed53f5f9@kernel.org> (raw)
In-Reply-To: <20260109-apple-dwc3-role-switch-v1-1-11623b0f6222@jannau.net>
On 09.01.26 11:13, Janne Grunau wrote:
> Ignore USB role switches if dwc3-apple is already in the desired state.
> The USB-C port controller on M2 and M1/M2 Pro/Max/Ultra devices issues
> additional interrupts which result in USB role switches to the already
> active role.
> Ignore these USB role switches to ensure the USB-C port controller and
> dwc3-apple are always in a consistent state. This matches the behaviour
> in __dwc3_set_mode() in core.c.
> Fixes detecting USB 2.0 and 3.x devices on the affected systems. The
> reset caused by the additional role switch appears to leave the USB
> devices in a state which prevents detection when the phy and dwc3 is
> brought back up again.
>
> Fixes: 0ec946d32ef7 ("usb: dwc3: Add Apple Silicon DWC3 glue layer driver")
> Cc: stable@vger.kernel.org
> Signed-off-by: Janne Grunau <j@jannau.net>
> ---
Reviewed-by: Sven Peter <sven@kernel.org>
Tested-by: Sven Peter <sven@kernel.org> # M1 mac mini and macbook air
thanks,
Sven
prev parent reply other threads:[~2026-01-13 6:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-09 10:13 [PATCH] usb: dwc3: apple: Ignore USB role switches to the active role Janne Grunau
2026-01-13 0:52 ` Thinh Nguyen
2026-01-13 6:58 ` Sven Peter [this message]
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