Re: [PATCH v6] usb: pci-quirks: always assert xHCI OS ownership

[sashiko-bot@kernel.org]

> The xHCI ownership protocol requires the OS driver to assert the HC OS
> Owned semaphore before using the host controller, then wait for HC BIOS
> Owned to clear if firmware owns it.
> 
> quirk_usb_handoff_xhci() currently asserts OS Owned only when BIOS Owned
> is already set. If firmware leaves BIOS Owned clear, Linux uses the xHC
> while both ownership semaphores remain clear.
> 
> The timeout fallback also clears BIOS Owned using the original register
> value, which can clear OS Owned at the same time.
> 
> On an AMD PROM21 xHCI controller (1022:43fc), this caused every S3
> resume to terminate Controller Restore State with USBSTS 0x401. Linux
> then reset the host controller, both root hubs and the USB Bluetooth
> adapter.
> [ ... ]
> Tested-by: McKenna Fan <blue_sun@tuta.io>
> Tested-by: Quinn Schive <quinnschive@hotmail.com>
> Tested-by: Bruno Filipe <bmilreu@gmail.com>
> Tested-by: Maciej Zonski <me@zonni.pl>
> Signed-off-by: Rishabh Jain <rishabh.jain1198@gmail.com>

Sashiko has reviewed this patch and found no issues.

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