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SubjectRe: [PATCH v4 0/3] scsi: fix internal write cache issue on usb hdd.
From
Hi Greg.

Would you check this patch-set ?

Thanks.

2012/6/14, Namjae Jeon <linkinjeon@gmail.com>:
> From: Namjae Jeon <namjae.jeon@samsung.com>
>
> The numbers of USB HDDs(All USB HDD I checked) does not respond
> correctly to scsi mode sense command for retrieving the write cache
> page status. Even though write cache is enabled by default, due to
> scsi driver assume that cache is not enabled which in turn might lead
> to loss of data since data still will be in cache.
> This result that all filesystems is not stable on USB HDD when the
> device is unplugged abruptly, even though these are having journaling
> feature. Our first trying is that scsi driver send ATA command
> (ATA Pass through, #58) to USB HDD after failure from normal routine to
> know write cache enable.
> We have known it is dangerous after testing several USB HDD. some of
> HDD is stalled by this command(A-DATA HDD). So we tried to make the
> patch James's suggestion(usb quirk) on version 2 that add product ID
> and verdor ID of USB HDD to USB quirk list after checking write cache.
> All filesystem will be stable on USB HDD registered in quirk list.
> And it will be updated continuously.
>
> scsi: set to WCE if usb cache quirk is present.
> usb: storage: add support for write cache quirk on usb hdd.
> usb: storage: update usb devices for write cache quirk in quirk.
>
> drivers/scsi/sd.c | 9 +++++++--
> include/scsi/scsi_device.h | 1 +
> drivers/usb/storage/scsiglue.c | 5 +++++
> drivers/usb/storage/usb.c | 5 ++++-
> include/linux/usb_usual.h | 4 +++-
> drivers/usb/storage/unusual_devs.h | 24 ++++++++++++++++++++++++
> Documentation/kernel-parameters.txt | 2 ++
> 7 files changed, 46 insertions(+), 4 deletions(-)
> --
> 1.7.9.5
>
>


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