Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII;
 format=flowed
Content-Transfer-Encoding: 7bit
Date:   Mon, 04 Nov 2019 08:59:11 +0800
From:   cang@codeaurora.org
To:     "Bean Huo (beanhuo)" <beanhuo@micron.com>
Cc:     asutoshd@codeaurora.org, nguyenb@codeaurora.org,
        rnayak@codeaurora.org, linux-scsi@vger.kernel.org,
        kernel-team@android.com, saravanak@google.com, salyzyn@google.com,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        Pedro Sousa <pedrom.sousa@synopsys.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Subhash Jadavani <subhashj@codeaurora.org>,
        Tomas Winkler <tomas.winkler@intel.com>,
        Venkat Gopalakrishnan <venkatg@codeaurora.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [EXT] [PATCH v1 1/6] scsi: ufs: Add device reset in link recovery
 path
In-Reply-To: <BN7PR08MB56845B4A5F206A319CAFD3B1DB7C0@BN7PR08MB5684.namprd08.prod.outlook.com>
References: <1572671016-883-1-git-send-email-cang@codeaurora.org>
 <1572671016-883-2-git-send-email-cang@codeaurora.org>
 <BN7PR08MB56845B4A5F206A319CAFD3B1DB7C0@BN7PR08MB5684.namprd08.prod.outlook.com>
Message-ID: <d46aa74f8623cc0b61b94bd4fcc25ce4@codeaurora.org>
User-Agent: Roundcube Webmail/1.2.5
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 2019-11-04 05:48, Bean Huo (beanhuo) wrote:
> Hi, Can Guo
> 
>> In order to recover from hibern8 exit failure, perform a reset in link 
>> recovery
>> path before issuing link start-up.
>> 
>> Signed-off-by: Can Guo <cang@codeaurora.org>
>> ---
>>  drivers/scsi/ufs/ufshcd.c | 3 +++
>>  1 file changed, 3 insertions(+)
>> 
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c 
>> index
>> c28c144..525f8e6 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -3859,6 +3859,9 @@ static int ufshcd_link_recovery(struct ufs_hba 
>> *hba)
>>  	ufshcd_set_eh_in_progress(hba);
>>  	spin_unlock_irqrestore(hba->host->host_lock, flags);
>> 
>> +	/* Reset the attached device */
>> +	ufshcd_vops_device_reset(hba);
>> +
>>  	ret = ufshcd_host_reset_and_restore(hba);
>> 
> There is time consumption in reset,  It is true that reset can
> hide/solve some issues.
> I don't know if you experienced issue resulting from an absent reset
> in this case mentioned in
> Patch commit comment.
> 

Hi Bean,

Yes, we did see some issues without this device reset here. For example,
link start-up failure and/or NOP-IN timeout during probe stage.

Best regards,
Can Guo.

>>  	spin_lock_irqsave(hba->host->host_lock, flags);
>> --
>> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora 
>> Forum,
>> a Linux Foundation Collaborative Project