Re: ExtScsiPassThru support for Logical SCSI devices

["Ravi Kumar Siadri" <siadriravikumaruefi@gmail.com>]

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Hi,

Can someone help me in clarifying my queries ??

Thanks,
Ravi Kumar

On Mon, Jun 10, 2019 at 3:55 PM Ravi Kumar Siadri <
siadriravikumaruefi@gmail.com> wrote:

> Hi all,
>
> I have couple of queries regarding the
> *EFI_EXT_SCSI_PASS_THRU_ATTRIBUTES_LOGICAL* attribute support in
> *EFI_EXT_SCSI_PASS_THRU_PROTOCOL*.
>
> *1. *
> *The Attributes field of the EFI_EXT_SCSI_PASS_THRU_PROTOCOL interface
> tells if the interface is for physical SCSI devices or logical SCSI
> devices. Drivers for non-RAID SCSI controllers will set both the
> EFI_EXT_SCSI_PASS_THRU_ATTRIBUTES_PHYSICAL, and the
> EFI_EXT_SCSI_PASS_THRU_ATTRIBUTES_LOGICAL bits.*
>
> If the Drivers is for non-RAID SCSI controllers why to set the
> EFI_EXT_SCSI_PASS_THRU_ATTRIBUTES_LOGICAL bit. Will there be any case that
> non-RAID SCSI controllers have Logical devices connected to it ??
>
> *2. *
> *Drivers for RAID controllers that allow access to the physical devices
> and logical devices will produce two EFI_EXT_SCSI_PASS_THRU_PROTOCOL
> interfaces:  *
> *One with the just the EFI_EXT_SCSI_PASS_THRU_ATTRIBUTES_PHYSICAL bit set
> and another with just the EFI_EXT_SCSI_PASS_THRU_ATTRIBUTES_LOGICAL bit
> set. One interface can be used to access the physical devices attached to
> the RAID controller, and the other can be used to access the logical
> devices attached to the RAID controller for its current configuration.*
>
> Any background why EFI_EXT_SCSI_PASS_THRU_PROTOCOL needed 2 instances ?
> why can't we install attributes EFI_EXT_SCSI_PASS_THRU_ATTRIBUTES_LOGICAL
> and EFI_EXT_SCSI_PASS_THRU_ATTRIBUTES_PHYSICAL on same Instance ??
> How User locates the Instance with
> EFI_EXT_SCSI_PASS_THRU_ATTRIBUTES_LOGICAL bit set and Instance with
> EFI_EXT_SCSI_PASS_THRU_ATTRIBUTES_PHYSICAL bit set. ??
>
> Thanks,
> Ravi Kumar
>
>

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