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Date:   Wed, 13 Nov 2019 11:22:25 +0800
From:   cang@codeaurora.org
To:     "Martin K. Petersen" <martin.petersen@oracle.com>
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>,
        linux-kernel@vger.kernel.org, Can Guo <cang@codeaurora.org>
Subject: Re: [PATCH v3 1/5] scsi: Adjust DBD setting in mode sense for caching
 mode page per LLD
In-Reply-To: <yq1tv78pjdz.fsf@oracle.com>
References: <1572670898-750-1-git-send-email-cang@codeaurora.org>
 <1572670898-750-2-git-send-email-cang@codeaurora.org>
 <yq1tv78pjdz.fsf@oracle.com>
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On 2019-11-13 11:03, Martin K. Petersen wrote:
> 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!

Hi Martin,

Thank you, good idea. I will make the change in your way.

Best regards,
Can Guo.