Re: [PATCH 1/5] usb: xhci: clear stale bandwidth data after hibernation

["Neronin, Niklas" <niklas.neronin@linux.intel.com>]

On 27/10/2026 11.52, Thorsten Leemhuis wrote:
> On 10/6/26 17:24, Niklas Neronin wrote:
>> Controllers using software managed bandwidth accounting maintain
>> periodic endpoint bandwidth information in struct 'xhci_interval_bw_table'.
>>
>> Each root hub port owns a bandwidth table and a list of TT bandwidth
>> domains, where each TT has its own bandwidth table. Virtual devices
>> reference the bandwidth table of their current bandwidth domain through
>> 'bw_table' or 'tt_info'.
> 
> What happened to this? This from what I see fixes a regression from the
> 7.1 cycle, so it would be good to finally resolve this for 7.4-rc1. But
> I see that Michal's review comment wasn't answered -- is that what we
> are waiting for. And I wonder if it was unwise to bundle this regression
> fix with other changed -- and if it should be resubmitted separately.

Planning to resubmit this separately, after the merge window, with minor
commit message improvements.

> 
>> Historically, resume from S4 re-allocated the entire xHCI driver state,
>> which implicitly cleared all bandwidth accounting data. After the
>> hibernation resume path was optimized to preserve parts of the driver
>> state, virtual devices and TT bandwidth information were freed and
>> recreated, but the root hub bandwidth tables were left intact.
>>
>> As a result, stale bandwidth accounting data could remain in the root
>> hub bandwidth tables across hibernation resume, leading to incorrect
>> bandwidth calculations after devices were rediscovered.
>>
>> Fix this by resetting all software bandwidth accounting state in
>> xhci_rh_bw_cleanup() so that resume starts with a clean bandwidth state.
>> This includes 'xhci->num_active_eps', which must remain consistent with
>> the cleared bandwidth tables.
> 
> BTW in case this needs to be resubmitted:
>> Fixes: <2a70e5dc0301> ("usb: xhci: optimize resuming from S4 (suspend-to-disk)")
> 
> Drop the "<" and the ">" please.

Good catch, I'll fix that.

Thanks,
Niklas