From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Mathias Nyman <mathias.nyman@linux.intel.com>
Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
Mario Limonciello <mario.limonciello@amd.com>,
Harry Wentland <harry.wentland@amd.com>
Subject: Re: [PATCH v2] usb: acpi: fix boot hang due to early incorrect 'tunneled' USB3 device links
Date: Thu, 24 Oct 2024 17:56:24 +0300 [thread overview]
Message-ID: <20241024145624.GI275077@black.fi.intel.com> (raw)
In-Reply-To: <20241024131355.3836538-1-mathias.nyman@linux.intel.com>
On Thu, Oct 24, 2024 at 04:13:55PM +0300, Mathias Nyman wrote:
> Fix a boot hang issue triggered when a USB3 device is incorrectly assumed
> to be tunneled over USB4, thus attempting to create a device link between
> the USB3 "consumer" device and the USB4 "supplier" Host Interface before
> the USB4 side is properly bound to a driver.
>
> This could happen if xhci isn't capable of detecting tunneled devices,
> but ACPI tables contain all info needed to assume device is tunneled.
> i.e. udev->tunnel_mode == USB_LINK_UNKNOWN.
>
> It turns out that even for actual tunneled USB3 devices it can't be
> assumed that the thunderbolt driver providing the tunnel is loaded
> before the tunneled USB3 device is created.
> The tunnel can be created by BIOS and remain in use by thunderbolt/USB4
> host driver once it loads.
>
> Solve this by making the device link "stateless", which doesn't create
> a driver presence order dependency between the supplier and consumer
> drivers.
> It still guarantees correct suspend/resume and shutdown ordering.
>
> cc: Mario Limonciello <mario.limonciello@amd.com>
> Fixes: f1bfb4a6fed6 ("usb: acpi: add device link between tunneled USB3 device and USB4 Host Interface")
> Tested-by: Harry Wentland <harry.wentland@amd.com>
> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
prev parent reply other threads:[~2024-10-24 14:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-24 13:13 [PATCH v2] usb: acpi: fix boot hang due to early incorrect 'tunneled' USB3 device links Mathias Nyman
2024-10-24 13:24 ` Mario Limonciello
2024-10-24 14:56 ` Mika Westerberg [this message]
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