From mboxrd@z Thu Jan 1 00:00:00 1970 From: Namjae Jeon Subject: [PATCH v4 1/3] scsi: set to WCE if usb cache quirk is present. Date: Mon, 11 Jun 2012 09:32:46 -0400 Message-ID: <1339421567-3137-1-git-send-email-linkinjeon@gmail.com> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: James.Bottomley@HansenPartnership.com, gregkh@linuxfoundation.org, mdharm-usb@one-eyed-alien.net, stern@rowland.harvard.edu, sshtylyov@mvista.com, bvanassche@acm.org Cc: linux-usb@vger.kernel.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Namjae Jeon , Namjae Jeon , Pankaj Kumar , Amit Sahrawat List-Id: linux-scsi@vger.kernel.org Make use of USB quirk method to identify such HDD while reading the cache status in sd_probe(). If cache quirk is present for the HDD, lets assume that cache is enabled and make WCE bit equal to 1. Signed-off-by: Namjae Jeon Signed-off-by: Pankaj Kumar Signed-off-by: Amit Sahrawat --- drivers/scsi/sd.c | 9 +++++++-- include/scsi/scsi_device.h | 1 + 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 6f0a4c6..e63e363 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -2259,8 +2259,13 @@ bad_sense: sd_printk(KERN_ERR, sdkp, "Asking for cache data failed\n"); defaults: - sd_printk(KERN_ERR, sdkp, "Assuming drive cache: write through\n"); - sdkp->WCE = 0; + if (sdp->wce_default_on) { + sd_printk(KERN_NOTICE, sdkp, "Assuming drive cache: write back\n"); + sdkp->WCE = 1; + } else { + sd_printk(KERN_ERR, sdkp, "Assuming drive cache: write through\n"); + sdkp->WCE = 0; + } sdkp->RCD = 0; sdkp->DPOFUA = 0; } diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index 6efb2e1..8be0247 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -152,6 +152,7 @@ struct scsi_device { unsigned no_read_disc_info:1; /* Avoid READ_DISC_INFO cmds */ unsigned no_read_capacity_16:1; /* Avoid READ_CAPACITY_16 cmds */ unsigned is_visible:1; /* is the device visible in sysfs */ + unsigned wce_default_on:1; /* Cache is ON by default */ DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */ struct list_head event_list; /* asserted events */ -- 1.7.9.5