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Date:   Tue, 22 Dec 2020 19:33:18 +0800
From:   Can Guo <cang@codeaurora.org>
To:     Stanley Chu <stanley.chu@mediatek.com>
Cc:     linux-scsi@vger.kernel.org, martin.petersen@oracle.com,
        avri.altman@wdc.com, alim.akhtar@samsung.com, jejb@linux.ibm.com,
        beanhuo@micron.com, asutoshd@codeaurora.org,
        matthias.bgg@gmail.com, bvanassche@acm.org,
        linux-mediatek@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        kuohong.wang@mediatek.com, peter.wang@mediatek.com,
        chun-hung.wu@mediatek.com, andy.teng@mediatek.com,
        chaotian.jing@mediatek.com, cc.chou@mediatek.com,
        jiajie.hao@mediatek.com, alice.chao@mediatek.com
Subject: Re: [PATCH v2 1/2] scsi: ufs: Fix possible power drain during system
 suspend
In-Reply-To: <20201222072905.32221-2-stanley.chu@mediatek.com>
References: <20201222072905.32221-1-stanley.chu@mediatek.com>
 <20201222072905.32221-2-stanley.chu@mediatek.com>
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On 2020-12-22 15:29, Stanley Chu wrote:
> Currently if device needs to do flush or BKOP operations,
> the device VCC power is kept during runtime-suspend period.
> 
> However, if system suspend is happening while device is
> runtime-suspended, such power may not be disabled successfully.
> 
> The reasons may be,
> 
> 1. If current PM level is the same as SPM level, device will
>    keep runtime-suspended by ufshcd_system_suspend().
> 
> 2. Flush recheck work may not be scheduled successfully
>    during system suspend period. If it can wake up the system,
>    this is also not the intention of the recheck work.
> 
> To fix this issue, simply runtime-resume the device if the flush
> is allowed during runtime suspend period. Flush capability will be
> disabled while leaving runtime suspend, and also not be allowed in
> system suspend period.
> 
> Fixes: 51dd905bd2f6 ("scsi: ufs: Fix WriteBooster flush during runtime 
> suspend")
> Reviewed-by: Chaotian Jing <chaotian.jing@mediatek.com>
> 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 e221add25a7e..9d61dc3eb842 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -8903,7 +8903,8 @@ int ufshcd_system_suspend(struct ufs_hba *hba)
>  	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))
> +	     hba->uic_link_state) &&
> +	     !hba->dev_info.b_rpm_dev_flush_capable)
>  		goto out;
> 
>  	if (pm_runtime_suspended(hba->dev)) {

Reviewed-by: Can Guo <cang@codeaurora.org>