Re: [PATCH v1 16/17] scsi: ufs: add delay before putting UFS rails in low power modes

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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
> 500us.
> 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 current
> +        * (atleast for 500us) from UFS rails (especially from VCCQ rail).
> +        * To avoid this situation, add 2ms delay before putting these UFS
> +        * rails in LPM mode.
> +        */
> +       if (!ufshcd_is_link_active(hba))
> +               usleep_range(2000, 2100);
> +

Shouldn't we define dev_quirks for this?

> +       /*
>          * If UFS device is either in UFS_Sleep turn off VCC rail to save some
>          * power.
>          *
> --
> 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
> --
> 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-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [SCSI Target Devel]     [Linux SCSI Target Infrastructure]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Linux IIO]     [Samba]     [Device Mapper]
  Powered by Linux