Re: [PATCH v2] xhci: pci: Disable soft retry for Renesas uPD720201

[Mathias Nyman <mathias.nyman@linux.intel.com>]

On 6/17/26 13:09, raoxu wrote:
> From: Xu Rao <raoxu@uniontech.com>
> 
> The Renesas uPD720201 xHCI controller can fail to complete
> a Stop Endpoint command after a transaction error on an interrupt
> endpoint when soft retry is used.
> 
> This was reproduced with this setup:
> 
>    xHCI: Renesas uPD720201, PCI ID 1912:0014 rev 03
>    dev:  USB Ethernet device with an integrated Genesys Logic
>          USB3.1 hub, USB ID 05e3:0626, and a Realtek RTL8153
>          Ethernet function, USB ID 0bda:8153
> 
> Reproducer:
> 
>    1. Plug the integrated USB hub and Ethernet device into the
>       1912:0014 xHCI controller.
>    2. Let r8152 bind to the 0bda:8153 RTL8153 Ethernet function
>       behind the integrated hub.
>    3. Bring the Ethernet device up.
>    4. Hot-unplug the device.
> 
> The host reports a transaction error on the RTL8153 interrupt
> endpoint, queues a soft reset, and later times out the Stop
> Endpoint command while disconnecting the device:
> 
>    Transfer error for slot 8 ep 6 on endpoint
>    Soft-reset ep 6, slot 8
>    Ignoring reset ep completion code of 1
>    xHCI host not responding to stop endpoint command
>    xHCI host controller not responding, assume dead
>    HC died; cleaning up
> 
> The Renesas 1912:0014 controller cannot safely use the xHCI soft
> retry path. Set XHCI_NO_SOFT_RETRY for this controller so
> transaction errors use the pre-soft-retry recovery path. With
> this quirk the same hot-unplug test no longer times out the Stop
> Endpoint command and the RTL8153 remains usable and stable.
> 
> Fixes: f8f80be501aa ("xhci: Use soft retry to recover faster from transaction errors")
> Cc: stable@vger.kernel.org
> Signed-off-by: Xu Rao <raoxu@uniontech.com>
> ---

Thanks, added

I'd appreciate your opinion on a related issue.
I'm thinking about trying to recover from these stop endpoint command timeouts.

While debugging this, did xHC controller otherwise seem somewhat functional?
Did you for example see port status change events, or transfer events
between queuing the stop endpoint command and the timeout?

Thanks
Mathias