scsi: ufs: optimize system suspend handling
Consider following sequence of events:
1. UFS is runtime suspended, link_state = Hibern8, device_state = sleep
2. System goes into system suspend, ufshcd_system_suspend() brings both
link and device to active state and then puts the device in Power_Down
state and link in OFF state.
3. System resumes at some later point in time, ufshcd_system_resume()
doesn't do anything as UFS state is runtime suspended. Note that link
is still on OFF state and device is in Power_Down state.
4. Now system again goes into suspend without any UFS accesses before it.
ufshcd_system_suspend() again brings both link and device to active
state and then puts the device in Power_Down state and link if OFF
state. But it's unnecessary to bring the link & device in active state
as both link and device are already in desired low power states. This
change fixes this issue by adding proper state checks in
ufshcd_system_suspend().
Reviewed-by: Gilad Broner <gbroner@codeaurora.org>
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
1 file changed