Re: [PATCH 1/1] xhci: dbc: support runtime suspend while DbC is in enabled state

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Jun 16, 2026 at 11:09:32AM +0300, Mathias Nyman wrote:
> Allow xHC to runtime suspend if DbC is in 'enabled' state for over
> 15 seconds without a connect.
> 
> Idea is that every time we go to 'enabled' state we make sure DbC runtime
> pm usage is '1' and save a timestamp. if the event loop still finds DbC in
> enabled state 15 seconds later then it decrease DbC runtime pm usage by
> calling pm_runtime_put().
> Enabled state is reached either when DbC is enabled by userspace or a
> connected/configured DbC is disconnected.
> 
> When a connect is detected we make sure DbC usage count is 1.
> 
> If DbC has been in 'enabled' state for 15 seconds and DbC usage is
> decreased to 0 by pm_runtime_put, then the whole xHC controller may
> runtime suspends to PCI D3 state if no other devices are using it
> 
> DbC sysfs file will show 'suspended' when xHC is suspended and will wake up
> and enable DbC at cable connect, or when user writes 'enable' to the file.
> 
> This patch was originally part of a larger DbC series, but dropped before
> the series was submitted to 7.2-rc1. The series has a locking issue in
> commit 520058b73ba3 ("xhci: dbc: serialize enabling and disabling dbc")
> which is also resolved by this patch
> 
> Fixes: 520058b73ba3 ("xhci: dbc: serialize enabling and disabling dbc")
> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
> ---
>  .../testing/sysfs-bus-pci-drivers-xhci_hcd    |  2 +-
>  drivers/usb/host/xhci-dbgcap.c                | 60 ++++++++++++++++++-
>  drivers/usb/host/xhci-dbgcap.h                |  3 +
>  3 files changed, 62 insertions(+), 3 deletions(-)

No "reported-by:"?