Re: [PATCH v2 2/2] scsi: ufs: Execute START_STOP_UNIT during init

[Evan Green]

On Fri, Sep 28, 2018 at 4:04 PM Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
>
> On Fri, Sep 28, 2018 at 04:02:03PM -0700, Evan Green wrote:
> > For UFS devices that are provisioned to have an initial power mode
> > (bInitPowerMode) of "sleep", Linux will currently fail to enumerate
> > the device. This is because the UFS specification says that the
> > device must get a START_STOP_UNIT SCSI command to wake the unit
> > up before other common initialization features like the device
> > descriptor will be available to be read.
>
> Yikes, this is just completely broken in terms of scsi compliance.
>
> I think we should simply not support such devices.

Really? It's part of the UFS spec. The document I have specifies that
I shouldn't reproduce without permission, but it's in JESD220A section
7.2.4 UFS-Sleep Power Mode.
-Evan