Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 07 Feb 2020 13:10:35 +0800 | From | Can Guo <> | Subject | Re: [PATCH v7 8/8] scsi: ufs: Select INITIAL adapt for HS Gear4 |
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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.
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