From: Janne Grunau <j@jannau.net>
To: Sven Peter <sven@svenpeter.dev>
Cc: Felipe Balbi <balbi@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Hector Martin <marcan@marcan.st>,
Alyssa Rosenzweig <alyssa@rosenzweig.io>,
Mark Kettenis <mark.kettenis@xs4all.nl>,
Rob Herring <robh+dt@kernel.org>,
linux-usb@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 2/2] usb: dwc3: Add role switch reset quirk for Apple DWC3
Date: Sat, 13 Nov 2021 12:05:52 +0100 [thread overview]
Message-ID: <20211113110552.GA10073@jannau.net> (raw)
In-Reply-To: <20211108170946.49689-2-sven@svenpeter.dev>
On 2021-11-08 18:09:46 +0100, Sven Peter wrote:
> As mad as it sounds, the dwc3 controller present on Apple SoCs must be
> reset and reinitialized whenever a device is unplugged from the root port
> and triggers a role switch notification from the USB PD controller.
>
> This is required for at least two reasons:
>
> - The USB2 D+/D- lines are connected through a stateful eUSB2 repeater
> which in turn is controlled by a variant of the TI TPS6598x USB PD
> chip. When the USB PD controller detects a hotplug event it resets
> the eUSB2 repeater. Afterwards, no new device is recognized before
> the DWC3 core and PHY are reset as well.
>
> - It's possible to completely break the dwc3 controller by switching
> it to device mode and unplugging the cable at just the wrong time.
> Even a CORESOFTRESET is not enough to allow new devices again.
> The only workaround is to trigger a hard reset of the entire
> dwc3 core. This also happens when running macOS on these
> machines.
This patch is necessary and works on M1 Max (Macbook Pro 14" 2021).
Tested with compatible = "apple,t6000,dwc3", "apple,dwc3", "snps,dwc3";.
Feel free to add
Tested-by: Janne Grunau <j@jannau.net>
Janne
next prev parent reply other threads:[~2021-11-13 11:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-08 17:09 [PATCH v2 1/2] dt-bindings: usb: Add Apple dwc3 bindings Sven Peter
2021-11-08 17:09 ` [PATCH v2 2/2] usb: dwc3: Add role switch reset quirk for Apple DWC3 Sven Peter
2021-11-13 11:05 ` Janne Grunau [this message]
2021-11-29 1:27 ` [PATCH v2 1/2] dt-bindings: usb: Add Apple dwc3 bindings Rob Herring
2021-11-29 22:34 ` Sven Peter
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