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[PATCH v1 03/17] scsi: ufs: optimize system suspend handling

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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().

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>

---
 drivers/scsi/ufs/ufshcd.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 388536e..9e3ec01 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5464,16 +5464,13 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
 	if (!hba || !hba->is_powered)
 		return 0;
 
-	if (pm_runtime_suspended(hba->dev)) {
-		if (hba->rpm_lvl == hba->spm_lvl)
-			/*
-			 * There is possibility that device may still be in
-			 * active state during the runtime suspend.
-			 */
-			if ((ufs_get_pm_lvl_to_dev_pwr_mode(hba->spm_lvl) ==
-			    hba->curr_dev_pwr_mode) && !hba->auto_bkops_enabled)
-				goto out;
+	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))
+		goto out;
 
+	if (pm_runtime_suspended(hba->dev)) {
 		/*
 		 * UFS device and/or UFS link low power states during runtime
 		 * suspend seems to be different than what is expected during
-- 
1.8.5.2

-- 
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Thread

[PATCH v1 00/17] add fixes, device quirks, error recovery, Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 04/17] scsi: ufs: avoid spurious UFS host controller interrupts Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 10/17] scsi: ufs: make error handling bit faster Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 08/17] scsi: ufs: split broken LCC quirk Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 12/17] scsi: ufs: add retry for query descriptors Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 16/17] scsi: ufs: add delay before putting UFS rails in low power modes Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 13/17] scsi: ufs: handle non spec compliant bkops behaviour by device Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 15/17] scsi: ufs: fix leakage during link off state Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 05/17] scsi: ufs: implement scsi host timeout handler Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 17/17] scsi: ufs-qcom: set PA_Local_TX_LCC_Enable before link startup Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 14/17] scsi: ufs: tune UniPro parameters to optimize hibern8 exit time Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 09/17] scsi: ufs: disable vccq if it's not needed by UFS device Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 06/17] scsi :ufs: verify hba controller hce reg value Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 11/17] scsi: ufs: add error recovery after DL NAC error Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 03/17] scsi: ufs: optimize system suspend handling Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 02/17] scsi: ufs: add option to change default UFS power management level Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 01/17] scsi: ufs-qcom: add number of lanes per direction Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200
  [PATCH v1 07/17] scsi: ufs: separate device and host quirks Yaniv Gardi <ygardi@codeaurora.org> - 2015-09-13 17:00 +0200

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