Commit eed5d2150752bd08b22333d739f3120151773d28

Authored by Rafael J. Wysocki
Committed by Greg Kroah-Hartman
1 parent eab072609e

PM / Runtime: Do not increment device usage counts before probing

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: Kevin Hilman <khilman@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Showing 1 changed file with 2 additions and 4 deletions Side-by-side Diff

... ... @@ -369,10 +369,9 @@
369 369 pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
370 370 drv->bus->name, __func__, dev_name(dev), drv->name);
371 371  
372   - pm_runtime_get_noresume(dev);
373 372 pm_runtime_barrier(dev);
374 373 ret = really_probe(dev, drv);
375   - pm_runtime_put_sync(dev);
  374 + pm_runtime_idle(dev);
376 375  
377 376 return ret;
378 377 }
379 378  
... ... @@ -419,9 +418,8 @@
419 418 ret = 0;
420 419 }
421 420 } else {
422   - pm_runtime_get_noresume(dev);
423 421 ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
424   - pm_runtime_put_sync(dev);
  422 + pm_runtime_idle(dev);
425 423 }
426 424 out_unlock:
427 425 device_unlock(dev);