On Thu, 2013-07-11 at 16:03 +0800, shuox....@intel.com wrote:
> From: Liu ShuoX <shuox....@intel.com>
>
> In shutdown progress, system is possible to do power transition
> (such as suspend-to-ram) in parallel. It is unreasonable. So,
> fixes it by adding a system_state checking and queue try_to_suspend
> again when system status is not running.
>
> Signed-off-by: Liu ShuoX <shuox....@intel.com>
> ---
> kernel/power/autosleep.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
Without this patch, we hit an hang issue on Android.
Scenario:
Kernel starts shutdown and calls all device driver's shutdown callback.
When a driver's shutdown is called, the last wakelock is released and
suspend-to-ram starts. However, as some driver's shut down callbacks
already shut down devices and disable runtime pm, the suspend-to-ram
calls driver's suspend callback without noticing that device is already
off and causes crash.
We know the drivers should be fixed, but can we also change generic
codes a little to make it stronger?
> diff --git a/kernel/power/autosleep.c b/kernel/power/autosleep.c
> index c6422ff..9012ecf 100644
> --- a/kernel/power/autosleep.c
> +++ b/kernel/power/autosleep.c
> @@ -32,7 +32,8 @@ static void try_to_suspend(struct work_struct *work)
>
> mutex_lock(&autosleep_lock);
>
> - if (!pm_save_wakeup_count(initial_count)) {
> + if (!pm_save_wakeup_count(initial_count) ||
> + system_state != SYSTEM_RUNNING) {
> mutex_unlock(&autosleep_lock);
> goto out;
> }
--
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