Re: [PATCH v2 2/2] MdeModulePkg/Bus/Ata/AtaAtapiPassThru: Fix UNUSED_VALUE Coverity issue

["Wu, Hao A" <hao.a.wu@intel.com>]

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It works for me, better to override by:
  Status = EFI_SUCCESS;

Best Regards,
Hao Wu

From: Ranbir Singh <rsingh@ventanamicro.com>
Sent: Wednesday, July 12, 2023 3:01 PM
To: Wu, Hao A <hao.a.wu@intel.com>
Cc: devel@edk2.groups.io; Ni, Ray <ray.ni@intel.com>
Subject: Re: [PATCH v2 2/2] MdeModulePkg/Bus/Ata/AtaAtapiPassThru: Fix UNUSED_VALUE Coverity issue

Thanks Hao for digging deeper into this.

The if block itself might get knocked off in Release mode when there is only a DEBUG statement inside it and hence Coverity might still complain. So, we can override the Status value in this scenario inside the if block and then proceed normally - let me know if this is acceptable and I will update the patch as below then

      if (EFI_ERROR (Status)) {
        DEBUG ((DEBUG_WARN, "Set Drive Parameters Fail, Status = %r\n", Status));
        /* Ignore Warning and proceed normally */
        Status = 0;
      }

Best Regards,
Ranbir Singh

On Wed, Jul 12, 2023 at 10:08 AM Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com>> wrote:
Really sorry,

After referring to the Information Technology - AT Attachment with Packet Interface (ATA/ATAPI) Specification,
It seems to me that the commands being executed in function SetDriveParameters() are not mandatory during device initialization.

1. INITIALIZE DEVICE PARAMETERS command (ID 0x91h):
This command got obsoleted since ATA/ATAPI-6 spec version.
Also, the return status of SetDriveParameters() is irrelevant with the execution result of this command.

2. SET MULTIPLE MODE command (ID 0xC6h):
My take is that this command is necessary if there is subsequent usage of command READ MULTIPLE, READ MULTIPLE EXT, WRITE MULTIPLE, or WRITE MULTIPLE EXT.
I do not find usage of the above 4 commands within edk2, so I think the successful execution of SET MULTIPLE MODE command is not mandatory for detecting hard disk device.

Based on the above findings, could you help to update the patch to:
      Status = SetDriveParameters (Instance, IdeChannel, IdeDevice, &DriveParameters, NULL);

      if (EFI_ERROR (Status)) {
        DEBUG ((DEBUG_WARN, "Set Drive Parameters Fail, Status = %r\n", Status));
      }

Will doing so still please Coverity?

Best Regards,
Hao Wu

> -----Original Message-----
> From: Ranbir Singh <rsingh@ventanamicro.com<mailto:rsingh@ventanamicro.com>>
> Sent: Friday, June 9, 2023 8:33 PM
> To: devel@edk2.groups.io<mailto:devel@edk2.groups.io>; rsingh@ventanamicro.com<mailto:rsingh@ventanamicro.com>
> Cc: Wu, Hao A <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com>>; Ni, Ray <ray.ni@intel.com<mailto:ray.ni@intel.com>>
> Subject: [PATCH v2 2/2] MdeModulePkg/Bus/Ata/AtaAtapiPassThru: Fix
> UNUSED_VALUE Coverity issue
>
> From: Ranbir Singh <Ranbir.Singh3@Dell.com<mailto:Ranbir.Singh3@Dell.com>>
>
> The return value stored in Status after call to SetDriveParameters
> is not made of any use thereafter and hence it remains as UNUSED.
>
> Add error check as is done after calls to SetDeviceTransferMode.
>
> Cc: Hao A Wu <hao.a.wu@intel.com<mailto:hao.a.wu@intel.com>>
> Cc: Ray Ni <ray.ni@intel.com<mailto:ray.ni@intel.com>>
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4204
> Signed-off-by: Ranbir Singh <Ranbir.Singh3@Dell.com<mailto:Ranbir.Singh3@Dell.com>>
> Signed-off-by: Ranbir Singh <rsingh@ventanamicro.com<mailto:rsingh@ventanamicro.com>>
> ---
>
> Notes:
>     Add error check instead of Status storage removal
>
>  MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c
> b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c
> index 75403886e44a..d04b1d95a7f5 100644
> --- a/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c
> +++ b/MdeModulePkg/Bus/Ata/AtaAtapiPassThru/IdeMode.c
> @@ -2549,13 +2549,18 @@ DetectAndConfigIdeDevice (
>      //
>
>      if (DeviceType == EfiIdeHarddisk) {
>
>        //
>
> -      // Init driver parameters
>
> +      // Init drive parameters
>
>        //
>
>        DriveParameters.Sector         = (UINT8)((ATA5_IDENTIFY_DATA
> *)(&Buffer.AtaData))->sectors_per_track;
>
>        DriveParameters.Heads          = (UINT8)(((ATA5_IDENTIFY_DATA
> *)(&Buffer.AtaData))->heads - 1);
>
>        DriveParameters.MultipleSector = (UINT8)((ATA5_IDENTIFY_DATA
> *)(&Buffer.AtaData))->multi_sector_cmd_max_sct_cnt;
>
>
>
>        Status = SetDriveParameters (Instance, IdeChannel, IdeDevice,
> &DriveParameters, NULL);
>
> +
>
> +      if (EFI_ERROR (Status)) {
>
> +        DEBUG ((DEBUG_ERROR, "Set Drive Parameters Fail, Status = %r\n",
> Status));
>
> +        continue;
>
> +      }
>
>      }
>
>
>
>      //
>
> --
> 2.34.1

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