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

[sashiko-bot@kernel.org]

> 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'.
> 
> 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.
> 
> Fixes: <2a70e5dc0301> ("usb: xhci: optimize resuming from S4 (suspend-to-disk)")
> Reported-by: Harald Judt <h.judt@gmx.at>
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=222071
> Suggested-by: Lovekesh Solanki <lovekeshsolanki00@gmail.com>
> Tested-by: Harald Judt <h.judt@gmx.at>
> Signed-off-by: Niklas Neronin <niklas.neronin@linux.intel.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261006152427.3735383-1-niklas.neronin@linux.intel.com?part=1