From: Evan Green <evgreen@chromium.org>
To: hch@infradead.org
Cc: Vinayak Holikatti <vinholikatti@gmail.com>,
jejb@linux.vnet.ibm.com, martin.petersen@oracle.com,
adrian.hunter@intel.com, stanislav.nijnikov@wdc.com,
linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
Doug Anderson <dianders@chromium.org>,
Gwendal Grignou <gwendal@chromium.org>
Subject: Re: [PATCH v2 2/2] scsi: ufs: Execute START_STOP_UNIT during init
Date: Fri, 28 Sep 2018 16:09:28 -0700 [thread overview]
Message-ID: <CAE=gft4iB_iHfZ10vtty1aC6BAevT_zGLd0Yh3P8=Cpg4pymew@mail.gmail.com> (raw)
In-Reply-To: <20180928230416.GA30772@infradead.org>
On Fri, Sep 28, 2018 at 4:04 PM Christoph Hellwig <hch@infradead.org> 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
prev parent reply other threads:[~2018-09-28 23:10 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-28 23:02 [PATCH v2 0/2] scsi: ufs: Enable bInitPowerMode of sleep Evan Green
2018-09-28 23:02 ` [PATCH v2 1/2] scsi: ufs: Allow SCSI commands early during init Evan Green
2018-09-28 23:02 ` [PATCH v2 2/2] scsi: ufs: Execute START_STOP_UNIT " Evan Green
2018-09-28 23:04 ` Christoph Hellwig
2018-09-28 23:09 ` Evan Green [this message]
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