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Date:   Tue, 11 Apr 2023 09:55:35 -0400
From:   Alan Stern <stern@rowland.harvard.edu>
To:     Jimmy Hu <hhhuuu@google.com>
Cc:     gregkh@linuxfoundation.org, badhri@google.com,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        stable@vger.kernel.org
Subject: Re: [PATCH] usb: core: hub: Disable autosuspend for VIA VL813 USB3.0
 hub
Message-ID: <ce727a7b-6954-4e4d-85c7-f91011b87108@rowland.harvard.edu>
References: <20230411083145.2214105-1-hhhuuu@google.com>
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On Tue, Apr 11, 2023 at 08:31:45AM +0000, Jimmy Hu wrote:
> The VIA VL813 USB3.0 hub appears to have an issue with autosuspend and
> detecting USB3 devices. This can be reproduced by connecting a USB3
> device to the hub after the hub enters autosuspend mode.
> 
> //connect the hub
> [  106.854204] usb 2-1: new SuperSpeed Gen 1 USB device number 2 using xhci-hcd
> [  107.084993] usb 2-1: New USB device found, idVendor=2109, idProduct=0813, bcdDevice=90.15
> [  107.094520] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
> [  107.111836] usb 2-1: Product: USB3.0 Hub
> [  107.116835] usb 2-1: Manufacturer: VIA Labs, Inc.
> [  107.314230] hub 2-1:1.0: USB hub found
> [  107.321356] hub 2-1:1.0: 4 ports detected
> 
> //the hub enters autosuspend mode
> [  107.738873] hub 2-1:1.0: hub_suspend
> [  107.922097] usb 2-1: usb auto-suspend, wakeup 1
> 
> //connect a USB3 device
> [  133.120060] usb 2-1: usb wakeup-resume
> [  133.160033] usb 2-1: Waited 0ms for CONNECT
> [  133.165423] usb 2-1: finish resume
> [  133.176919] hub 2-1:1.0: hub_resume
> [  133.188026] usb 2-1-port3: status 0263 change 0041
> [  133.323585] hub 2-1:1.0: state 7 ports 4 chg 0008 evt 0008
> [  133.342423] usb 2-1-port3: link state change
> [  133.358154] usb 2-1-port3: status 0263, change 0040, 5.0 Gb/s

This status value indicates that the port is in the U3 suspend state.  
Maybe the port needs to be put back into U0 before it can be reset.

> [  133.875150] usb 2-1-port3: not reset yet, waiting 10ms
> [  133.895502] usb 2-1-port3: not reset yet, waiting 10ms
> [  133.918239] usb 2-1-port3: not reset yet, waiting 200ms
> [  134.139529] usb 2-1-port3: not reset yet, waiting 200ms
> [  134.365296] usb 2-1-port3: not reset yet, waiting 200ms
> [  134.590185] usb 2-1-port3: not reset yet, waiting 200ms
> [  134.641330] hub 2-1:1.0: state 7 ports 4 chg 0000 evt 0008
> [  134.658880] hub 2-1:1.0: hub_suspend
> [  134.792908] usb 2-1: usb auto-suspend, wakeup 1
> 
> Disabling autosuspend for this hub resolves the issue.

It may be possible to fix the problem.  You should try that before 
giving up.

Alan Stern