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31620fc1c8
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 commit520058b73b("xhci: dbc: serialize enabling and disabling dbc") which is also resolved by this patch Fixes:520058b73b("xhci: dbc: serialize enabling and disabling dbc") Reported-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com> Closes: https://lore.kernel.org/linux-usb/9ce24ff5-efab-4089-92d7-709862d68e6d@intel.com Tested-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Link: https://patch.msgid.link/20260616100916.2234205-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>