Re: [PATCH v1 16/17] scsi: ufs: add delay before putting UFS rails in low power modes
Date: Mon Oct 26 2015 - 11:08:10 EST
> 2015-09-13 23:52 GMT+09:00 Yaniv Gardi <ygardi@xxxxxxxxxxxxxx>:
>> We put the UFS device in sleep state & UFS link in hibern8 state during
>> runtime suspaned. After this we put all the UFS rails in low power
>> modes immediately but it seems some devices may still draw more than
>> sleep current from UFS rails (especially from VCCQ rail) atleast for
>> To avoid this situation, this change adds 2ms delay before putting
>> these UFS rails in LPM mode.
>> Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
>> Signed-off-by: Yaniv Gardi <ygardi@xxxxxxxxxxxxxx>
>> drivers/scsi/ufs/ufshcd.c | 9 +++++++++
>> 1 file changed, 9 insertions(+)
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index 20b4c0e..786df28 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -5694,6 +5694,15 @@ out:
>> static void ufshcd_vreg_set_lpm(struct ufs_hba *hba)
>> + * It seems some UFS devices may keep drawing more than sleep
>> + * (atleast for 500us) from UFS rails (especially from VCCQ
>> + * To avoid this situation, add 2ms delay before putting these
>> + * rails in LPM mode.
>> + */
>> + if (!ufshcd_is_link_active(hba))
>> + usleep_range(2000, 2100);
> Shouldn't we define dev_quirks for this?
as you suggested, in v2 i added a device quirk for that.
>> + /*
>> * If UFS device is either in UFS_Sleep turn off VCC rail to
>> save some
>> * power.
>> QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a
>> member of Code Aurora Forum, hosted by The Linux Foundation
>> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
>> the body of a message to majordomo@xxxxxxxxxxxxxxx
>> More majordomo info at http://vger.kernel.org/majordomo-info.html
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/