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From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: Can Guo <cang@codeaurora.org>
Cc: asutoshd@codeaurora.org, nguyenb@codeaurora.org,
	rnayak@codeaurora.org, linux-scsi@vger.kernel.org,
	kernel-team@android.com, saravanak@google.com,
	salyzyn@google.com, "James E.J. Bottomley" <jejb@linux.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	linux-kernel@vger.kernel.org (open list)
Subject: Re: [PATCH v3 1/5] scsi: Adjust DBD setting in mode sense for caching mode page per LLD
Date: Tue, 12 Nov 2019 22:03:52 -0500	[thread overview]
Message-ID: <yq1tv78pjdz.fsf@oracle.com> (raw)
In-Reply-To: <1572670898-750-2-git-send-email-cang@codeaurora.org> (Can Guo's message of "Fri, 1 Nov 2019 22:01:34 -0700")


Can,

> Host sends MODE_SENSE_10 with caching mode page, to check if the
> device supports the cache feature.  UFS JEDEC standards require DBD
> field to be set to 1.

UFS requires DBD for all MODE SENSE(10) invocations, not just for
accessing the caching mode page. I think the flag name needs to reflect
this.

Also, I do not particularly like this being a scsi_host flag. All the
other flags we have in this department are per scsi_device.

My recommendation would be to add a set_dbd_for_ms flag to struct
scsi_device and then do:

	sdev->set_dbd_for_ms = 1;

in ufshcd_slave_alloc() mirroring the existing:

        sdev->use_10_for_ms = 1;

This makes the MODE SENSE tweakery consistent.

Thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

  parent reply	other threads:[~2019-11-13  3:06 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-02  5:01 [PATCH v3 0/5] UFS driver general fixes bundle 1 Can Guo
2019-11-02  5:01 ` [PATCH v3 1/5] scsi: Adjust DBD setting in mode sense for caching mode page per LLD Can Guo
2019-11-03 21:16   ` [EXT] " Bean Huo (beanhuo)
2019-11-13  3:03   ` Martin K. Petersen [this message]
2019-11-13  3:22     ` cang
2019-11-02  5:01 ` [PATCH v3 2/5] scsi: ufs: Set DBD setting in mode sense for caching mode page Can Guo
2019-11-03 21:17   ` [EXT] " Bean Huo (beanhuo)
2019-11-02  5:01 ` [PATCH v3 3/5] scsi: ufs: Release clock if DMA map fails Can Guo
2019-11-02  5:01 ` [PATCH v3 4/5] scsi: ufs: Do not clear the DL layer timers Can Guo
2019-11-02  5:01 ` [PATCH v3 5/5] scsi: ufs: Do not free irq in suspend Can Guo
  -- strict thread matches above, loose matches on Subject: below --
2019-11-02  1:20 [PATCH v3 0/5] UFS driver general fixes bundle 1 Can Guo
2019-11-02  1:20 ` [PATCH v3 1/5] scsi: Adjust DBD setting in mode sense for caching mode page per LLD Can Guo

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