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From: Can Guo <cang@codeaurora.org>
To: Avri Altman <Avri.Altman@wdc.com>
Cc: asutoshd@codeaurora.org, nguyenb@codeaurora.org,
	hongwus@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>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	Bean Huo <beanhuo@micron.com>,
	Stanley Chu <stanley.chu@mediatek.com>,
	Bart Van Assche <bvanassche@acm.org>,
	Venkat Gopalakrishnan <venkatg@codeaurora.org>,
	Tomas Winkler <tomas.winkler@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Pedro Sousa <sousa@synopsys.com>,
	open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v7 8/8] scsi: ufs: Select INITIAL adapt for HS Gear4
Date: Fri, 07 Feb 2020 13:10:35 +0800	[thread overview]
Message-ID: <ebbaf825f4a78b1a21da347e8c6d5531@codeaurora.org> (raw)
In-Reply-To: <08101e2924d6262579beec488fcbd93f@codeaurora.org>

On 2020-02-07 10:56, Can Guo wrote:
> On 2020-02-06 21:20, Avri Altman wrote:
>> Hi Can,
>> 
>> 
>>> ADAPT is added specifically for HS Gear4 mode only, select INITIAL 
>>> adapt
>>> before do power mode change to G4 and select no adapt before switch 
>>> to
>>> non-G4 modes.
>> 
>> UFSHCI 3.0 says:
>> 7.4.1 Adapt
>> The use of Adapt isn't mandatory but the specification provides some
>> guidelines on its use.
>> The HCI should perform an Initial Adapt in the following cases if the
>> link is running at HS-G4
>> speed:
>>  - If DME_RESET is initiated.
>>  - If an unused line is activated for HS-G4.
>>  - If UECDME.EC is triggered with bit 3 set to '1'.
>>  - If a change between Rate A and Rate B in HS-G4 is performed.
>> 
>> If it's not mandatory - why are we setting this for all vendors on all
>> platforms?
>> Or am I miss-reading the spec?
>> 
>> Thanks,
>> Avri
> 
> Hi Avri,
> 
> Yes, it is not mandatory, but I don't know a flash vendor that
> refuses to use ADAPT so far, it is even recommended by flash vendors.
> So there is no meaning of adding a specific quirk for it, as all flash
> vendors need this quirk. Otherwise, we would need to add another vops
> to allow platform vendors to control it before send PMC.
> 
> Any other suggestions?
> 
> FYI, ADAPT sequence is used to train an M-RX equalizer. It gives both
> sides better signal integrity against the influence caused by
> temperature and voltage variations. ADAPT is also used by Quality of
> Service Monitoring for HS-G4.
> 
> As for the usage of it, here is just setting the type of it before
> PMC to HS-G4, HW will use ADAPT, only if both sides support ADAPT,
> when it is required as what the spec is saying.
> 
> Thanks,
> 
> Can Guo.

Hi Avri,

I will drop this one for now as it may take some time to nail down it.
I will come back with a separate patch series for it later.

Thanks for the review.

Can Guo.

      reply	other threads:[~2020-02-07  5:10 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1580978008-9327-1-git-send-email-cang@codeaurora.org>
2020-02-06  8:33 ` [PATCH v7 1/8] scsi: ufs: Flush exception event before suspend Can Guo
2020-02-06  8:33 ` [PATCH v7 2/8] scsi: ufs: set load before setting voltage in regulators Can Guo
2020-02-06  8:33 ` [PATCH v7 3/8] scsi: ufs: Remove the check before call setup clock notify vops Can Guo
2020-02-06  8:33 ` [PATCH v7 4/8] scsi: ufs-qcom: Adjust bus bandwidth voting and unvoting Can Guo
2020-02-06  8:33 ` [PATCH v7 5/8] scsi: ufs: Fix ufshcd_hold() caused scheduling while atomic Can Guo
2020-02-06 10:28   ` Avri Altman
2020-02-10  1:28     ` Can Guo
2020-02-10  1:59       ` Can Guo
2020-02-10  8:23         ` Avri Altman
2020-02-06  8:33 ` [PATCH v7 6/8] scsi: ufs: Add dev ref clock gating wait time support Can Guo
2020-02-06  8:33 ` [PATCH v7 7/8] scsi: ufs-qcom: Delay specific time before gate ref clk Can Guo
2020-02-06 20:33   ` Bjorn Andersson
2020-02-07  1:09     ` Can Guo
2020-02-07  2:10       ` Bjorn Andersson
2020-02-08  0:10         ` Can Guo
2020-02-06  8:33 ` [PATCH v7 8/8] scsi: ufs: Select INITIAL adapt for HS Gear4 Can Guo
2020-02-06 13:20   ` Avri Altman
2020-02-07  2:56     ` Can Guo
2020-02-07  5:10       ` Can Guo [this message]

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