Re: AMD Strix Halo USB4: 20/40 Gbit/s negotiation with RJ45 and original host-reset patch regression

[Mario Limonciello <superm1@kernel.org>]

On 9/16/26 02:38, Mika Westerberg wrote:
> Hi,
> 
> On Tue, Sep 15, 2026 at 03:42:43PM -0500, Mario Limonciello wrote:
>> On 9/15/26 07:49, Mika Westerberg wrote:
>>> Hi,
>>>
>>> On Tue, Sep 15, 2026 at 01:21:39PM +0200, Nils Arnold wrote:
>>>> Hello Sanath, Mario, Mika and Basavaraj,
>>>>
>>>> I would like to add test evidence from two Strix Halo hosts to this
>>>> USB4 reset discussion. My reset test used a backport of the ORIGINAL
>>>> f1de1fc5f632 commit, not the newer deferred-reset implementation.
>>>> I have not tested the revisions discussed on September 15.
>>>
>>> Okay the last message on the thread I asked if we should revert the commit
>>> for v7.3-rcX and then try to get the "better" fix into v7.4. At least what
>>> I understood it seems to solve the issue without the deadlock and killing
>>> the whole host interface underneath everybody else.
>>
>> FWIW to Nils I left a note on that thread and agree with Mika.
>>
>>>
>>> Once we have that patch, you can test and see if that helps in your case
>>> too. Now that we know AMD guys can CC you when they submit it.
>>
>> One thing I'd like to note though; I would rather that we keep out of tree
>> modules out of the conversation on the kernel mailing list when it comes to
>> upstream behavior.
>>
>> There are multiple ways to do xdomain tunnels in the kernel, and we should
>> collectively fixate our time and energy on bugs related to those instead of
>> PoC out of tree drivers.
> 
> Fully agree. But the same behaviour is with the in-tree Thunderbolt
> networking and stream (and maybe DMA test) drivers so those should at least
> be working with the AMD controller without wedging.

Yes and no.  That out of tree driver might be configured as a module, 
but at least I haven't audited it.  It could be causing other problems 
too when it accesses certain symbols.

For our own sanity I suggest we work with those in tree drivers and 
untainted kernel.  If the problem can reproduce with those we can work 
on fixing it.