linux-kernel - Re: [PATCH v4 4/5] scsi: ufs: Do not clear the DL layer timers

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Date:   Mon, 25 Nov 2019 07:39:05 +0000
From:   cang@...eaurora.org
To:     Avri Altman <Avri.Altman@....com>
Cc:     asutoshd@...eaurora.org, nguyenb@...eaurora.org,
        rnayak@...eaurora.org, linux-scsi@...r.kernel.org,
        kernel-team@...roid.com, saravanak@...gle.com, salyzyn@...gle.com,
        Alim Akhtar <alim.akhtar@...sung.com>,
        Pedro Sousa <pedrom.sousa@...opsys.com>,
        "James E.J. Bottomley" <jejb@...ux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        Stanley Chu <stanley.chu@...iatek.com>,
        Bean Huo <beanhuo@...ron.com>,
        Tomas Winkler <tomas.winkler@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Allison Randal <allison@...utok.net>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 4/5] scsi: ufs: Do not clear the DL layer timers

On 2019-11-25 15:22, Avri Altman wrote:
>> >
>> > During power mode change, PACP_PWR_Req frame sends
>> PAPowerModeUserData
>> > parameters (and they are considered valid by device if Flags[4] -
>> > UserDataValid bit is set in the same frame).
>> > Currently we don't set these PAPowerModeUserData parameters and
>> > hardware always sets UserDataValid bit which would clear all the DL
>> > layer timeout values of the peer device after the power mode change.
>> >
>> > This change sets the PAPowerModeUserData[0..5] to UniPro specification
>> > recommended default values, in addition we are also setting the
>> > relevant
>> > DME_LOCAL_* timer attributes as required by UFS HCI specification.
>> >
>> > Signed-off-by: Can Guo <cang@...eaurora.org>
>> Reviewed-by Avri Altman <avri.altman@....com>
> BTW, I noticed that you are only updating the TC0 registers.
> Why not setting the TC1 registers as well?
> 
> Thanks,
> Avri

Hi Avri,

In the HCI spec, it goes

Currently, UFS uses TC0 only. Therefore, setting the following values 
are not needed:
 DME_ Local_FC1ProtectionTimeOutVal
 DME_ Local_TC1ReplayTimeOutVal
 DME_ Local_ AFC1ReqTimeOutVal

Best Regards,
Can Guo.