• Rafael J. Wysocki's avatar
    PM / Runtime: Do not increment device usage counts before probing · eed5d215
    Rafael J. Wysocki authored
    The pm_runtime_get_noresume() calls before really_probe() and
    before executing __device_attach() for each driver on the
    device's bus cause problems to happen if probing fails and if the
    driver has enabled runtime PM for the device in its .probe()
    callback.  Namely, in that case, if the device has been resumed
    by the driver after enabling its runtime PM and if it turns out that
    .probe() should return an error, the driver is supposed to suspend
    the device and disable its runtime PM before exiting .probe().
    However, because the device's runtime PM usage counter was
    incremented by the core before calling .probe(), the driver's attempt
    to suspend the device will not succeed and the device will remain in
    the full-power state after the failing .probe() has returned.
    
    To fix this issue, remove the pm_runtime_get_noresume() calls from
    driver_probe_device() and from device_attach() and replace the
    corresponding pm_runtime_put_sync() calls with pm_runtime_idle()
    to preserve the existing behavior (which is to check if the device
    is idle and to suspend it eventually in that case after probing).
    Reported-and-tested-by: default avatarKevin Hilman <khilman@ti.com>
    Reviewed-by: default avatarKevin Hilman <khilman@ti.com>
    Signed-off-by: default avatarRafael J. Wysocki <rjw@sisk.pl>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    eed5d215
dd.c 15.5 KB