Re: [PATCH v2] thunderbolt: Fix connection issue with Pluggable UD-4VPD dock

[Mario Limonciello <mario.limonciello@amd.com>]

On 11/5/2024 08:25, Rick wrote:
> Hi Mario,
> 
> On 05-11-2024 15:21, Mario Limonciello wrote:
>> On 11/5/2024 08:02, Mika Westerberg wrote:
>>> On Tue, Nov 05, 2024 at 11:54:55AM +0100, Greg KH wrote:
>>>> On Tue, Nov 05, 2024 at 12:31:57PM +0200, Mika Westerberg wrote:
>>>>> Rick reported that his Pluggable USB4 dock does not work anymore after
>>>>> upgrading to v6.10 kernel.
>>
>> If I'm not mistaken Rick was talking about a Dell WD19TB dock which is 
>> TBT3, not a Pluggable USB4 dock.
>>
> 
> To prevent any confusion; I don't own any Dell WD19TB dock. I had these 
> issues with the UD-4VPD dock.

Oh!  I see, you were saying a "me too" to the thread which was about 
WD19TB.  Thanks for clarifying.

> 
>> Nonetheless I wouldn't be surprised if other docks and devices have 
>> problems.
>>
>> We have an internal report at AMD of something similar happening with 
>> TBT3 storage devices.  After this lands I'll ask that team that 
>> reported it to see if it helped them too.
>>
>>>>>
>>>>> It looks like commit c6ca1ac9f472 ("thunderbolt: Increase sideband
>>>>> access polling delay") makes the device router enumeration happen 
>>>>> later
>>>>> than what might be expected by the dock (although there is no such 
>>>>> limit
>>>>> in the USB4 spec) which probably makes it assume there is something
>>>>> wrong with the high-speed link and reset it. After the link is 
>>>>> reset the
>>>>> same issue happens again and again.
>>>>>
>>>>> For this reason lower the sideband access delay from 5ms to 1ms. This
>>>>> seems to work fine according to Rick's testing.
>>>>>
>>>>> Reported-by: Rick Lahaye <rick@581238.xyz>
>>>>> Closes: https://lore.kernel.org/linux- 
>>>>> usb/000f01db247b$d10e1520$732a3f60$@581238.xyz/
>>>>> Tested-by: Rick Lahaye <rick@581238.xyz>
>>>>> Fixes: c6ca1ac9f472 ("thunderbolt: Increase sideband access polling 
>>>>> delay")
>>>>> Cc: stable@vger.kernel.org
>>>>> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
>>>>
>>>> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>>
>>
>>> Thanks!
>>>
>>> Applied to thunderbolt.git/fixes.
>>
>> I'm a few hours late to the party, but if you update the commit 
>> message for my above comment feel free to add my tag too.
>>
>> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
>>
> 
> Kind regards,
> Rick Lahaye
> 
>