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From:   Can Guo <cang@qti.qualcomm.com>
To:     asutoshd@codeaurora.org, nguyenb@codeaurora.org,
        rnayak@codeaurora.org, linux-scsi@vger.kernel.org,
        kernel-team@android.com, saravanak@google.com, salyzyn@google.com,
        cang@codeaurora.org
Cc:     Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        Pedro Sousa <pedrom.sousa@synopsys.com>,
        "James E.J. Bottomley" <jejb@linux.ibm.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Stanley Chu <stanley.chu@mediatek.com>,
        Bean Huo <beanhuo@micron.com>,
        Subhash Jadavani <subhashj@codeaurora.org>,
        Tomas Winkler <tomas.winkler@intel.com>,
        linux-kernel@vger.kernel.org (open list)
Subject: [PATCH v3 2/5] scsi: ufs: Set DBD setting in mode sense for caching mode page
Date:   Fri,  1 Nov 2019 18:20:27 -0700
Message-Id: <1572657631-25749-3-git-send-email-cang@qti.qualcomm.com>
In-Reply-To: <1572657631-25749-1-git-send-email-cang@qti.qualcomm.com>
References: <1572657631-25749-1-git-send-email-cang@qti.qualcomm.com>
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From: Can Guo <cang@codeaurora.org>

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

Some card vendors are more strict and check the DBD field, hence
respond with CHECK_CONDITION (Sense key set to ILLEGAL_REQUEST and
ASC set to INVALID FIELD IN CDB).
As a result of the CHECK_CONDITION response, host assumes that the
device doesn't support the cache feature and doesn't send
SYNCHRONIZE_CACHE commands to flush the device cache.
This can result in data corruption in case of sudden power down, when
there is data stored in the device cache.

This patch fixes the DBD field setting in case of caching mode page.

Signed-off-by: Can Guo <cang@codeaurora.org>
---
 drivers/scsi/ufs/ufshcd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 0026199..0a6b8f9 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -8353,6 +8353,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	host->max_channel = UFSHCD_MAX_CHANNEL;
 	host->unique_id = host->host_no;
 	host->max_cmd_len = UFS_CDB_SIZE;
+	host->set_dbd_for_caching = 1;
 
 	hba->max_pwr_info.is_valid = false;
 
-- 
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