Re: [edk2-devel] [PATCH 1/1] MdePkg/UefiScsiLib: Set FUA bit for synchronous SCSI Write operations

["Zhiguang Liu" <zhiguang.liu@intel.com>]

Hi Christopher

Could you please give more information about this code change?
For example, which Spec the code change is based on.

Thanks
Zhiguang

> -----Original Message-----
> From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf Of
> Zurcher, Christopher J
> Sent: Saturday, February 22, 2020 10:12 AM
> To: devel@edk2.groups.io
> Cc: Kinney, Michael D <michael.d.kinney@intel.com>; Wang, Jian J
> <jian.j.wang@intel.com>; Gao, Liming <liming.gao@intel.com>
> Subject: [edk2-devel] [PATCH 1/1] MdePkg/UefiScsiLib: Set FUA bit for
> synchronous SCSI Write operations
> 
> The FUA (Force Unit Access) bit forces data to be written directly to disk
> instead of the write cache. This prevents data from being lost if a shutdown
> or reset is requested immediately after a SCSI write operation.
> 
> Cc: Michael D Kinney <michael.d.kinney@intel.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Signed-off-by: Christopher J Zurcher <christopher.j.zurcher@intel.com>
> ---
>  MdePkg/Library/UefiScsiLib/UefiScsiLib.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/MdePkg/Library/UefiScsiLib/UefiScsiLib.c
> b/MdePkg/Library/UefiScsiLib/UefiScsiLib.c
> index 13a2a1912c..cf78f131bd 100644
> --- a/MdePkg/Library/UefiScsiLib/UefiScsiLib.c
> +++ b/MdePkg/Library/UefiScsiLib/UefiScsiLib.c
> @@ -1,7 +1,7 @@
>  /** @file
>    UEFI SCSI Library implementation
> 
> -  Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
> +  Copyright (c) 2006 - 2020, Intel Corporation. All rights
> + reserved.<BR>
>    SPDX-License-Identifier: BSD-2-Clause-Patent
> 
>  **/
> @@ -1055,15 +1055,16 @@ ScsiWrite10Command (
>    ZeroMem (&CommandPacket, sizeof
> (EFI_SCSI_IO_SCSI_REQUEST_PACKET));
>    ZeroMem (Cdb, EFI_SCSI_OP_LENGTH_TEN);
> 
> -  CommandPacket.Timeout         = Timeout;
> -  CommandPacket.OutDataBuffer    = DataBuffer;
> -  CommandPacket.SenseData       = SenseData;
> -  CommandPacket.OutTransferLength= *DataLength;
> -  CommandPacket.Cdb             = Cdb;
> +  CommandPacket.Timeout           = Timeout;
> +  CommandPacket.OutDataBuffer     = DataBuffer;
> +  CommandPacket.SenseData         = SenseData;
> +  CommandPacket.OutTransferLength = *DataLength;
> +  CommandPacket.Cdb               = Cdb;
>    //
>    // Fill Cdb for Write (10) Command
>    //
>    Cdb[0]                        = EFI_SCSI_OP_WRITE10;
> +  Cdb[1]                        = BIT3; //FUA bit (Force Unit Access)
>    WriteUnaligned32 ((UINT32 *)&Cdb[2], SwapBytes32 (StartLba));
>    WriteUnaligned16 ((UINT16 *)&Cdb[7], SwapBytes16 ((UINT16)
> SectorSize));
> 
> @@ -1263,6 +1264,7 @@ ScsiWrite16Command (
>    // Fill Cdb for Write (16) Command
>    //
>    Cdb[0]                        = EFI_SCSI_OP_WRITE16;
> +  Cdb[1]                        = BIT3; //FUA bit (Force Unit Access)
>    WriteUnaligned64 ((UINT64 *)&Cdb[2], SwapBytes64 (StartLba));
>    WriteUnaligned32 ((UINT32 *)&Cdb[10], SwapBytes32 (SectorSize));
> 
> --
> 2.16.2.windows.1
> 
> 
>