[PATCH v2 1/2] scsi: ufs: Fix possible power drain during system suspend

[Stanley Chu]

Currently if device needs to do flush or BKOP operations,
the device VCC power is kept during runtime-suspend period.

However, if system suspend is happening while device is
runtime-suspended, such power may not be disabled successfully.

The reasons may be,

1. If current PM level is the same as SPM level, device will
   keep runtime-suspended by ufshcd_system_suspend().

2. Flush recheck work may not be scheduled successfully
   during system suspend period. If it can wake up the system,
   this is also not the intention of the recheck work.

To fix this issue, simply runtime-resume the device if the flush
is allowed during runtime suspend period. Flush capability will be
disabled while leaving runtime suspend, and also not be allowed in
system suspend period.

Fixes: 51dd905bd2f6 ("scsi: ufs: Fix WriteBooster flush during runtime suspend")
Reviewed-by: Chaotian Jing <chaotian.jing at mediatek.com>
Signed-off-by: Stanley Chu <stanley.chu at mediatek.com>
---
 drivers/scsi/ufs/ufshcd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index e221add25a7e..9d61dc3eb842 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -8903,7 +8903,8 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
 	if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) ==
 	     hba->curr_dev_pwr_mode) &&
 	    (ufs_get_pm_lvl_to_link_pwr_state(hba->spm_lvl) ==
-	     hba->uic_link_state))
+	     hba->uic_link_state) &&
+	     !hba->dev_info.b_rpm_dev_flush_capable)
 		goto out;
 
 	if (pm_runtime_suspended(hba->dev)) {
-- 
2.18.0