lkml.org 
[lkml]   [2015]   [Oct]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 03/17] scsi: ufs: optimize system suspend handling
Date
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 20c5b5d..00964f9 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -5459,16 +5459,13 @@ 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
--
QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation


\
 
 \ /
  Last update: 2015-10-26 17:01    [W:0.153 / U:0.236 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site