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From:   Avri Altman <Avri.Altman@wdc.com>
To:     Can Guo <cang@codeaurora.org>,
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        open list <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2 1/1] scsi: ufs: Enable block layer runtime PM for
 well-known logical units
Thread-Topic: [PATCH v2 1/1] scsi: ufs: Enable block layer runtime PM for
 well-known logical units
Thread-Index: AQHWAlBr6MxaJV41pE6Y/SVj7ognQqhZL8+Q
Date:   Wed, 25 Mar 2020 13:11:46 +0000
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>=20
> For the genernal UFS SCSI devices, block layer RPM is enabled for them
> when they are probed by their driver. However block layer RPM is not
> enabled for UFS well-known SCSI devices.
>=20
> As UFS SCSI devices have their corresponding BSG char devices, accessing
> these BSG char devices may result in sending requests to the SCSI devices
> through their request queues. If BSG IOCTL sends a request to a well-know=
n
> SCSI device when hba is not runtime active, as block layer RPM is not
> eanbled for the well-known SCSI device, hba, which is at the top of its
> parent chain, shall not be resumed, then unexpected error would happen.
While at it, can you fix the ufs-bsg as well?
Add this call to ufs_bsg_probe() and revert commit 74e5e468b664
(scsi: ufs-bsg: Wake the device before sending raw upiu commands) ?

Thanks,
Avri