[PATCH v1 1/2] scsi: ufs: set device as default active power mode during initialization only
Currently ufshcd_probe_hba() always sets device status as "active". This shall be by an assumption that device is already in active state during the boot stage before kernel.
However, if link is configured as "off" state and device is requested to enter "sleep" or "powerdown" power mode during suspend flow, device will NOT be waken up to "active" power mode during resume flow because device is already set as "active" power mode in ufhcd_probe_hba().
Fix it by setting device as default active power mode during initialization only, and skipping changing mode during PM flow in ufshcd_probe_hba().
Fixes: 7caf489b99a4 (scsi: ufs: issue link starup 2 times if device isn't active) Cc: Alim Akhtar alim.akhtar@samsung.com Cc: Avri Altman avri.altman@wdc.com Cc: Bart Van Assche bvanassche@acm.org Cc: Bean Huo beanhuo@micron.com Cc: Can Guo cang@codeaurora.org Cc: Matthias Brugger matthias.bgg@gmail.com Cc: Subhash Jadavani subhashj@codeaurora.org Cc: stable@vger.kernel.org Signed-off-by: Stanley Chu stanley.chu@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 ed02a704c1c2..9abb7085a5d0 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -6986,7 +6986,8 @@ static int ufshcd_probe_hba(struct ufs_hba *hba) ufshcd_tune_unipro_params(hba);
/* UFS device is also active now */ - ufshcd_set_ufs_dev_active(hba); + if (!hba->pm_op_in_progress) + ufshcd_set_ufs_dev_active(hba); ufshcd_force_reset_auto_bkops(hba); hba->wlun_dev_clr_ua = true;
Hi Stanley,
On 2019-12-30 00:12, Stanley Chu wrote:
Currently ufshcd_probe_hba() always sets device status as "active". This shall be by an assumption that device is already in active state during the boot stage before kernel.
However, if link is configured as "off" state and device is requested to enter "sleep" or "powerdown" power mode during suspend flow, device will NOT be waken up to "active" power mode during resume flow because device is already set as "active" power mode in ufhcd_probe_hba().
Fix it by setting device as default active power mode during initialization only, and skipping changing mode during PM flow in ufshcd_probe_hba().
Fixes: 7caf489b99a4 (scsi: ufs: issue link starup 2 times if device isn't active) Cc: Alim Akhtar alim.akhtar@samsung.com Cc: Avri Altman avri.altman@wdc.com Cc: Bart Van Assche bvanassche@acm.org Cc: Bean Huo beanhuo@micron.com Cc: Can Guo cang@codeaurora.org Cc: Matthias Brugger matthias.bgg@gmail.com Cc: Subhash Jadavani subhashj@codeaurora.org Cc: stable@vger.kernel.org Signed-off-by: Stanley Chu stanley.chu@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 ed02a704c1c2..9abb7085a5d0 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -6986,7 +6986,8 @@ static int ufshcd_probe_hba(struct ufs_hba *hba) ufshcd_tune_unipro_params(hba);
/* UFS device is also active now */
- ufshcd_set_ufs_dev_active(hba);
- if (!hba->pm_op_in_progress)
ufshcd_set_ufs_dev_active(hba);
I see that there's a get_sync done before. So, how would the suspend be triggered in that case?
Thanks, asd
Hi Asutosh,
I see that there's a get_sync done before. So, how would the suspend be triggered in that case?
Would you mean pm_runtime_get_sync() in ufshcd_init()? If yes, it will only happen during initialization.
The runtime resume path may go through ufshcd_probe_hba() without ufshcd_init() invoked before, for example,
ufshcd_probe_hba+0xe10/0x1874 ufshcd_host_reset_and_restore+0x114/0x1a4 ufshcd_resume+0x1d0/0x480 ufshcd_runtime_resume+0x40/0x188 ufshcd_pltfrm_runtime_resume+0x10/0x18 pm_generic_runtime_resume+0x24/0x44 __rpm_callback+0x100/0x250 rpm_resume+0x548/0x7c8 rpm_resume+0x2b4/0x7c8 rpm_resume+0x2b4/0x7c8 rpm_resume+0x2b4/0x7c8 pm_runtime_work+0x9c/0xa0 process_one_work+0x210/0x4e0 worker_thread+0x390/0x520 kthread+0x154/0x18c ret_from_fork+0x10/0x18
This case happens if link is in "off" state while resume.
Thanks, Stanley
On 2019-12-31 09:07, Stanley Chu wrote:
Hi Asutosh,
I see that there's a get_sync done before. So, how would the suspend be triggered in that case?
Would you mean pm_runtime_get_sync() in ufshcd_init()? If yes, it will only happen during initialization.
The runtime resume path may go through ufshcd_probe_hba() without ufshcd_init() invoked before, for example,
ufshcd_probe_hba+0xe10/0x1874 ufshcd_host_reset_and_restore+0x114/0x1a4 ufshcd_resume+0x1d0/0x480 ufshcd_runtime_resume+0x40/0x188 ufshcd_pltfrm_runtime_resume+0x10/0x18 pm_generic_runtime_resume+0x24/0x44 __rpm_callback+0x100/0x250 rpm_resume+0x548/0x7c8 rpm_resume+0x2b4/0x7c8 rpm_resume+0x2b4/0x7c8 rpm_resume+0x2b4/0x7c8 pm_runtime_work+0x9c/0xa0 process_one_work+0x210/0x4e0 worker_thread+0x390/0x520 kthread+0x154/0x18c ret_from_fork+0x10/0x18
This case happens if link is in "off" state while resume.
Thanks, Stanley
Hi Stanley,
I see skipping ufshcd_set_ufs_dev_active() in ufshcd_probe_hba() if it is called from ufshcd_resume() path is the purpose here.
If so, then ufshcd_set_dev_pwr_mode() would be called, meaning SSU command will be sent. Why is this SSU command needed to be sent after a full host reset and restore? Is ufshcd_probe_hba() not enough to make UFS device fully functional?
<snip> } else if (ufshcd_is_link_off(hba)) { ret = ufshcd_host_reset_and_restore(hba); /* * ufshcd_host_reset_and_restore() should have already * set the link state as active */ if (ret || !ufshcd_is_link_active(hba)) goto vendor_suspend; }
if (!ufshcd_is_ufs_dev_active(hba)) { ret = ufshcd_set_dev_pwr_mode(hba, UFS_ACTIVE_PWR_MODE); if (ret) goto set_old_link_state; } <snip>
Thanks,
Can Guo.
Hi Can,
Hi Stanley,
I see skipping ufshcd_set_ufs_dev_active() in ufshcd_probe_hba() if it is called from ufshcd_resume() path is the purpose here.
If so, then ufshcd_set_dev_pwr_mode() would be called, meaning SSU command will be sent. Why is this SSU command needed to be sent after a full host reset and restore? Is ufshcd_probe_hba() not enough to make UFS device fully functional?
After resume (for both runtime resume and system resume), device power mode shall be back to "Active" to service incoming requests.
I see two cases need device power mode transition during resume flow 1. Device Power Mode = Sleep 2. Device Power Mode = PowerDown
For 1, ufshcd_probe_hba() is not invoked during resume flow, hba->curr_dev_pwr_mode = SLEEP, thus ufshcd_resume() can invoke ufshcd_set_dev_pwr_mode() to change device power mode.
For 2, ufshcd_probe_hba() is invoked during resume flow, before this fix, hba->curr_dev_pwr_mode will be set to ACTIVE (note that only this flag is set as ACTIVE, but device may be still in PowerDown state if device power is not fully shutdown or device HW reset is not executed before resume), in the end, ufshcd_resume() will not invoke ufshcd_set_dev_pwr_mode() to send SSU command to make device change back to Active power mode.
But if device is fully reset before resume (not by current mainstream driver), device can be already in "Active" power mode after power on again during resume flow. In this case, it is OK to set hba->curr_dev_pwr_mode as ACTIVE in ufshcd_probe_hba() and SSU command is not necessary.
Thanks, Stanley
Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek
Hi Can,
On Tue, 2019-12-31 at 12:22 +0800, Stanley Chu wrote:
Hi Can,
Hi Stanley,
I see skipping ufshcd_set_ufs_dev_active() in ufshcd_probe_hba() if it is called from ufshcd_resume() path is the purpose here.
If so, then ufshcd_set_dev_pwr_mode() would be called, meaning SSU command will be sent. Why is this SSU command needed to be sent after a full host reset and restore? Is ufshcd_probe_hba() not enough to make UFS device fully functional?
After resume (for both runtime resume and system resume), device power mode shall be back to "Active" to service incoming requests.
I see two cases need device power mode transition during resume flow
- Device Power Mode = Sleep
- Device Power Mode = PowerDown
For 1, ufshcd_probe_hba() is not invoked during resume flow, hba->curr_dev_pwr_mode = SLEEP, thus ufshcd_resume() can invoke ufshcd_set_dev_pwr_mode() to change device power mode.
For 2, ufshcd_probe_hba() is invoked during resume flow, before this fix, hba->curr_dev_pwr_mode will be set to ACTIVE (note that only this flag is set as ACTIVE, but device may be still in PowerDown state if device power is not fully shutdown or device HW reset is not executed before resume), in the end, ufshcd_resume() will not invoke ufshcd_set_dev_pwr_mode() to send SSU command to make device change back to Active power mode.
But if device is fully reset before resume (not by current mainstream driver), device can be already in "Active" power mode after power on again during resume flow. In this case, it is OK to set hba->curr_dev_pwr_mode as ACTIVE in ufshcd_probe_hba() and SSU command is not necessary.
Thanks, Stanley
I think currently the assumption in ufshcd_probe_hba() that "device shall be already in Active power mode" makes sense because many device commands will be sent to device in ufshcd_probe_hba() but device is not promised to handle those commands in PowerDown power mode according to UFS spec.
So, maybe always ensuring device being Active power mode before leaving ufshcd_probe_hba() is more reasonable. If so, I will drop this patch first.
Thanks so much for your reviews.
Happy new year!
Thanks, Stanley
On 2019-12-31 15:44, Stanley Chu wrote:
Hi Can,
On Tue, 2019-12-31 at 12:22 +0800, Stanley Chu wrote:
Hi Can,
Hi Stanley,
I see skipping ufshcd_set_ufs_dev_active() in ufshcd_probe_hba() if it is called from ufshcd_resume() path is the purpose here.
If so, then ufshcd_set_dev_pwr_mode() would be called, meaning SSU command will be sent. Why is this SSU command needed to be sent after a full host reset and restore? Is ufshcd_probe_hba() not enough to make UFS device fully functional?
After resume (for both runtime resume and system resume), device power mode shall be back to "Active" to service incoming requests.
I see two cases need device power mode transition during resume flow
- Device Power Mode = Sleep
- Device Power Mode = PowerDown
For 1, ufshcd_probe_hba() is not invoked during resume flow, hba->curr_dev_pwr_mode = SLEEP, thus ufshcd_resume() can invoke ufshcd_set_dev_pwr_mode() to change device power mode.
For 2, ufshcd_probe_hba() is invoked during resume flow, before this fix, hba->curr_dev_pwr_mode will be set to ACTIVE (note that only this flag is set as ACTIVE, but device may be still in PowerDown state if device power is not fully shutdown or device HW reset is not executed before resume), in the end, ufshcd_resume() will not invoke ufshcd_set_dev_pwr_mode() to send SSU command to make device change back to Active power mode.
But if device is fully reset before resume (not by current mainstream driver), device can be already in "Active" power mode after power on again during resume flow. In this case, it is OK to set hba->curr_dev_pwr_mode as ACTIVE in ufshcd_probe_hba() and SSU command is not necessary.
Thanks, Stanley
I think currently the assumption in ufshcd_probe_hba() that "device shall be already in Active power mode" makes sense because many device commands will be sent to device in ufshcd_probe_hba() but device is not promised to handle those commands in PowerDown power mode according to UFS spec.
So, maybe always ensuring device being Active power mode before leaving ufshcd_probe_hba() is more reasonable. If so, I will drop this patch first.
Thanks so much for your reviews.
Happy new year!
Thanks, Stanley
Hi Stanley,
I missed this mail before I hit send. In current code, as per my understanding, UFS device's power state should be Active after ufshcd_link_startup() returns. If I am wrong, please feel free to correct me.
Due to you are almost trying to revert commit 7caf489b99a42a, I am just wondering if you encounter failure/error caused by it.
Happy new year to you too!
Thanks,
Can Guo
Hi Can,
On Tue, 2019-12-31 at 16:35 +0800, Can Guo wrote:
Hi Stanley,
I missed this mail before I hit send. In current code, as per my understanding, UFS device's power state should be Active after ufshcd_link_startup() returns. If I am wrong, please feel free to correct me.
Yes, this assumption of ufshcd_probe_hba() is true so I will drop this patch. Thanks for remind.
Due to you are almost trying to revert commit 7caf489b99a42a, I am just wondering if you encounter failure/error caused by it.
Yes, we actually have some doubts from the commit message of "scsi: ufs: issue link startup 2 times if device isn't active"
If we configured system suspend as device=PowerDown/Link=LinkDown mode, during resume, the 1st link startup will be successful, and after that device could be accessed normally so it shall be already in Active power mode. We did not find devices which need twice linkup for normal work.
And because the 1st linkup is OK, the forced 2nd linkup by commit "scsi: ufs: issue link startup 2 times if device isn't active" leads to link lost and finally the 3rd linkup is made again by retry mechanism in ufshcd_link_startup() and be successful. So a linkup performance issue is introduced here: We actually need one-time linkup only but finally got 3 linkup operations.
According to the UFS spec, all reset types (including POR and Host UniPro Warm Reset which both may happen in above configurations) other than LU reset, UFS device power mode shall return to Sleep mode or Active mode depending on bInitPowerMode, by default, it's Active mode.
So we are curious that why enforcing twice linkup is necessary here? Could you kindly help us clarify this?
If anything wrong in above description, please feel free to correct me.
Happy new year to you too!
Thanks,
Can Guo
Thanks,
Stanley
Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek
On 2020-01-02 14:38, Stanley Chu wrote:
Hi Can,
On Tue, 2019-12-31 at 16:35 +0800, Can Guo wrote:
Hi Stanley,
I missed this mail before I hit send. In current code, as per my understanding, UFS device's power state should be Active after ufshcd_link_startup() returns. If I am wrong, please feel free to correct me.
Yes, this assumption of ufshcd_probe_hba() is true so I will drop this patch. Thanks for remind.
Due to you are almost trying to revert commit 7caf489b99a42a, I am just wondering if you encounter failure/error caused by it.
Yes, we actually have some doubts from the commit message of "scsi: ufs: issue link startup 2 times if device isn't active"
If we configured system suspend as device=PowerDown/Link=LinkDown mode, during resume, the 1st link startup will be successful, and after that device could be accessed normally so it shall be already in Active power mode. We did not find devices which need twice linkup for normal work.
And because the 1st linkup is OK, the forced 2nd linkup by commit "scsi: ufs: issue link startup 2 times if device isn't active" leads to link lost and finally the 3rd linkup is made again by retry mechanism in ufshcd_link_startup() and be successful. So a linkup performance issue is introduced here: We actually need one-time linkup only but finally got 3 linkup operations.
According to the UFS spec, all reset types (including POR and Host UniPro Warm Reset which both may happen in above configurations) other than LU reset, UFS device power mode shall return to Sleep mode or Active mode depending on bInitPowerMode, by default, it's Active mode.
So we are curious that why enforcing twice linkup is necessary here? Could you kindly help us clarify this?
If anything wrong in above description, please feel free to correct me.
Hi Stanley,
Above description is correct. The reason why the UFS device becomes Active after the 1st link startup in your experiment is due to you set spm_lvl to 5, during system suspend, UFS device is powered down. When resume kicks start, the UFS device is power cycled once.
Moreover, if you set rpm_lvl to 5, during runtime suspend, if bkops is enabled, the UFS device will not be powered off, meaning when runtime resume kicks start, the UFS device is not power cycled, in this case, we need 3 times of link startup.
Does above explain?
Thanks,
Can Guo.
Happy new year to you too!
Thanks,
Can Guo
Thanks,
Stanley
Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek
On 2020-01-03 09:51, Can Guo wrote:
On 2020-01-02 14:38, Stanley Chu wrote:
Hi Can,
On Tue, 2019-12-31 at 16:35 +0800, Can Guo wrote:
Hi Stanley,
I missed this mail before I hit send. In current code, as per my understanding, UFS device's power state should be Active after ufshcd_link_startup() returns. If I am wrong, please feel free to correct me.
Yes, this assumption of ufshcd_probe_hba() is true so I will drop this patch. Thanks for remind.
Due to you are almost trying to revert commit 7caf489b99a42a, I am just wondering if you encounter failure/error caused by it.
Yes, we actually have some doubts from the commit message of "scsi: ufs: issue link startup 2 times if device isn't active"
If we configured system suspend as device=PowerDown/Link=LinkDown mode, during resume, the 1st link startup will be successful, and after that device could be accessed normally so it shall be already in Active power mode. We did not find devices which need twice linkup for normal work.
And because the 1st linkup is OK, the forced 2nd linkup by commit "scsi: ufs: issue link startup 2 times if device isn't active" leads to link lost and finally the 3rd linkup is made again by retry mechanism in ufshcd_link_startup() and be successful. So a linkup performance issue is introduced here: We actually need one-time linkup only but finally got 3 linkup operations.
According to the UFS spec, all reset types (including POR and Host UniPro Warm Reset which both may happen in above configurations) other than LU reset, UFS device power mode shall return to Sleep mode or Active mode depending on bInitPowerMode, by default, it's Active mode.
So we are curious that why enforcing twice linkup is necessary here? Could you kindly help us clarify this?
If anything wrong in above description, please feel free to correct me.
Hi Stanley,
Above description is correct. The reason why the UFS device becomes Active after the 1st link startup in your experiment is due to you set spm_lvl to 5, during system suspend, UFS device is powered down. When resume kicks start, the UFS device is power cycled once.
Moreover, if you set rpm_lvl to 5, during runtime suspend, if bkops is enabled, the UFS device will not be powered off, meaning when runtime resume kicks start, the UFS device is not power cycled, in this case, we need 3 times of link startup.
Does above explain?
Thanks,
Can Guo.
Hi Stanley,
Sorry, typo before. I meant if set rpm_lvl/spm_lvl to 5, during suspend, if is_lu_power_on_wp is set, the UFS device will not be fully powered off (only VCC is down), meaning when resume kicks start, the UFS device is not power cycled, in this case, we need 3 times of link startup.
Regards,
Can Guo.
Happy new year to you too!
Thanks,
Can Guo
Thanks,
Stanley
Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek
Hi Can,
On Fri, 2020-01-03 at 13:28 +0800, Can Guo wrote:
Hi Stanley,
Above description is correct. The reason why the UFS device becomes Active after the 1st link startup in your experiment is due to you set spm_lvl to 5, during system suspend, UFS device is powered down. When resume kicks start, the UFS device is power cycled once.
Moreover, if you set rpm_lvl to 5, during runtime suspend, if bkops is enabled, the UFS device will not be powered off, meaning when runtime resume kicks start, the UFS device is not power cycled, in this case, we need 3 times of link startup.
Does above explain?
Thanks,
Can Guo.
Hi Stanley,
Sorry, typo before. I meant if set rpm_lvl/spm_lvl to 5, during suspend, if is_lu_power_on_wp is set, the UFS device will not be fully powered off (only VCC is down), meaning when resume kicks start, the UFS device is not power cycled, in this case, we need 3 times of link startup.
Regards,
Can Guo.
Hi Can,
Very sorry for late responding this thread.
Now I would like to focus on 3-times link startup behavior found in our platform because this dramatically downgrade resume performance.
According to your description, then could the driver set "link_startup_again" as true only if "is_lu_power_on_wp" is set to avoid unnecessary three-times link startup in other cases?
In addition, for the scenario you mentioned: "the UFS device will not be fully powered off (only VCC is down), meaning when resume kicks start, the UFS device is not power cycled":
1. Actually I tried to set xpm_lvl=5, and enforced "is_lu_power_on_wp" as true for evaluation, but found device can be still back to Active PowerMode (can be accessed normally) after one-time link startup after resumed.
Only VCC is down and VCCQ2 is kept during suspend in my evaluation.
2. In this scenario, during resume the peer device shall have "UniPro Warm Reset" triggered by the first link start-up and then device power mode shall become Active according to UFS specification.
So what device power mode did you see after the first link startup in this scenario? Or any other conditions to make device need "link_startup_again"?
Thanks, Stanley
Hi Stanley, I am aware that this discussion is already concluded, Just pointing out a small issue that might ease your mind further.
Thanks, Avri
Hi Can,
On Tue, 2019-12-31 at 16:35 +0800, Can Guo wrote:
Hi Stanley,
I missed this mail before I hit send. In current code, as per my understanding, UFS device's power state should be Active after ufshcd_link_startup() returns. If I am wrong, please feel free to correct me.
Yes, this assumption of ufshcd_probe_hba() is true so I will drop this patch. Thanks for remind.
Due to you are almost trying to revert commit 7caf489b99a42a, I am just wondering if you encounter failure/error caused by it.
Yes, we actually have some doubts from the commit message of "scsi: ufs: issue link startup 2 times if device isn't active"
If we configured system suspend as device=PowerDown/Link=LinkDown mode, during resume, the 1st link startup will be successful, and after that device could be accessed normally so it shall be already in Active power mode. We did not find devices which need twice linkup for normal work.
And because the 1st linkup is OK, the forced 2nd linkup by commit "scsi: ufs: issue link startup 2 times if device isn't active" leads to link lost and finally the 3rd linkup is made again by retry mechanism in ufshcd_link_startup() and be successful. So a linkup performance issue is introduced here: We actually need one-time linkup only but finally got 3 linkup operations.
According to the UFS spec, all reset types (including POR and Host UniPro Warm Reset which both may happen in above configurations) other than LU reset, UFS device power mode shall return to Sleep mode or Active mode depending on bInitPowerMode, by default, it's Active mode.
As for bInitPowerMode - please see the discussion in https://www.mail-archive.com/linux-scsi@vger.kernel.org/msg78262.html
So we are curious that why enforcing twice linkup is necessary here? Could you kindly help us clarify this?
On 2019-12-31 12:22, Stanley Chu wrote:
Hi Can,
Hi Stanley,
I see skipping ufshcd_set_ufs_dev_active() in ufshcd_probe_hba() if it is called from ufshcd_resume() path is the purpose here.
If so, then ufshcd_set_dev_pwr_mode() would be called, meaning SSU command will be sent. Why is this SSU command needed to be sent after a full host reset and restore? Is ufshcd_probe_hba() not enough to make UFS device fully functional?
After resume (for both runtime resume and system resume), device power mode shall be back to "Active" to service incoming requests.
I see two cases need device power mode transition during resume flow
- Device Power Mode = Sleep
- Device Power Mode = PowerDown
For 1, ufshcd_probe_hba() is not invoked during resume flow, hba->curr_dev_pwr_mode = SLEEP, thus ufshcd_resume() can invoke ufshcd_set_dev_pwr_mode() to change device power mode.
For 2, ufshcd_probe_hba() is invoked during resume flow, before this fix, hba->curr_dev_pwr_mode will be set to ACTIVE (note that only this flag is set as ACTIVE, but device may be still in PowerDown state if device power is not fully shutdown or device HW reset is not executed before resume), in the end, ufshcd_resume() will not invoke ufshcd_set_dev_pwr_mode() to send SSU command to make device change back to Active power mode.
Hi Stanley,
Isn't below change fixing the problem you are saying above? With it, after ufshcd_link_startup(), UFS device's power mode will become Active anyways. Do you mean below change is not working properly and you are removing it?
commit 7caf489b99a42a9017ef3d733912aea8794677e7 Author: subhashj@codeaurora.org subhashj@codeaurora.org Date: Wed Nov 23 16:32:20 2016 -0800
scsi: ufs: issue link starup 2 times if device isn't active
If we issue the link startup to the device while its UniPro state is LinkDown (and device state is sleep/power-down) then link startup will not move the device state to Active. Device will only move to active state if the link starup is issued when its UniPro state is LinkUp. So in this case, we would have to issue the link startup 2 times to make sure that device moves to active state.
Thanks,
Can Guo
But if device is fully reset before resume (not by current mainstream driver), device can be already in "Active" power mode after power on again during resume flow. In this case, it is OK to set hba->curr_dev_pwr_mode as ACTIVE in ufshcd_probe_hba() and SSU command is not necessary.
Thanks, Stanley
Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek
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