Re: [PATCH v2 0/2] thunderbolt: Fix S4 resume incongruities

[Kenneth Crudup <kenny@panix.com>]

On 1/19/26 11:59, Mario Limonciello (AMD) (kernel.org) wrote:

> On 1/17/2026 10:57 AM, Katiyar, Pooja wrote:
> 
>>> I have confirmation the hack patch does help the issue for us too.
>>>
>>> If your patch doesn't work another logical solution could be to destroy
>>> all the tunnels as part of the PM freeze callback (not just the DP
>>> resources).  Maybe even unify the suspend and freeze codepaths for more
>>> opportunities for code reuse?
>>>
>>
>> Thanks for confirming the hack patch helps!
>>
>> We are actually working on a solution that releases the DP resources and
>> suspends the switch as part of the freeze sequence. This way the 
>> hibernation
>> image that is stored doesn't contain any active tunnels, and during 
>> resume
>> we get a DP hotplug notification for a new tunnel, similar to S5. So far
>> this patch is working fine but is under review.
>>
> 
> Thanks.  If you want early testing from us too before you're ready to 
> post publicly feel free to ping it offline to me too.

I'd like to get a CC: on that, too.

I've been testing that hack patch and will test further later tonight.

The issue I'm trying to chase down (and not sure if any of this will 
help with this, I wonder if it's really BIOS/EC related) is often times 
that after a suspend (or hibernate, but I use "suspend then hibernate", 
which I think does both and chooses which to use upon resume) and then 
connect to a different dock (or setup) from the one I'd suspended with, 
sometimes I have to unplug/replug my TB cable, otherwise I either get no 
recognition of my new display setup (and sometimes TB devices) or it'll 
try and use the same monitor resolution of the previously-connected 
monitor (as if the TB subsystem doesn't recognize things have changed).

-Kenny

-- 
Kenneth R. Crudup / Sr. SW Engineer, Scott County Consulting, Orange 
County CA