[T10] Question about NCQ H2D transmission be postponed when receive X_RDY

[James C Hatfield]

This appears to be a question for the SATA-IO Digital WG instead of T10.
I'll forward this question for their advice.

Thank You !!!
-----------------------------------------------------------------
Jim Hatfield
Seagate Technology LLC
   e-mail:  James.C.Hatfield at seagate.com
   s-mail:  389 Disc Drive;  Longmont, CO 80503 USA
   voice:  720-684-2120
   fax....: 720-684-2711
   cell...: 720-771-8914

On Fri, Sep 30, 2016 at 5:05 AM, Guojian (F) <guojian111 at hisilicon.com>
wrote:

>
>
>
>
> *发件人:* aidepei
> *发送时间:* 2016年9月30日 16:18
> *收件人:* Guojian (F)
> *主题:* Question about NCQ H2D transmission be postponed when receive X_RDY
>
>
>
> Hi,
>
> I have confusion about NCQ H2D tansmission.
>
>
>
>
>
> According to SATA spec 3.2(9.6.3 Link transmit state machine)
>
>
>
> LT1: HL_SendChkRdy state, this state is entered if a frame transmission
> has been requested by the host Transport layer.
>
>
>
> If in this state, the Link layer transmits X_RDYp and waits for X_RDYp or
> R_RDYp  from the Phy layer.
>
>
>
> NOTE 43 - It is possible that both the host and the device simultaneously
> request frame transmission by transmitting X_RDYp . If the host receives
> X_RDYp
>
> while transmitting X_RDYp , the host shall back off and enter the L_R
> cvWaitFifo state, *postponing its desired frame transmission until the
> device has completed its frame transmission and the bus is*
>
> *idle. *
>
>
>
> Transition LT1:1, if the host Link layer receives R_RDYp from the Phy
> layer, the Link layer shall make a transition to the LT3: L_SendSOF state.
>
>
>
> Transition LT1:2, if the host Link layer receives X_RDYp  from the Phy
> layer, the Link layer shall make a transition to the LR 2: L_RcvWaitFifo
> state.
>
>
>
>
>
>
>
> Consider following scenario:
>
> host adapter is sending X_RDYp for H2D(NCQ command) but receive X_RDYp for
> DMA SETUP FIS. After complete reception of DMA SETUP FIS, link layer
> retransmits H2D(NCQ command), it will result in SATA device aborting the
> command(NCQ data phase interrupted by H2D).
>
>
>
>
>
> My question is :
>
> In this scenario,
>
> 1)      the H2D(NCQ command) should be postponed in link layer until the
> device completed its frame transmission or
>
> 2)      link layer should reports error to transport layer because  X_RDY
> conflicts
>
> which one is correct?
>
>
>
> Thanks for your help.
>
>
>
>
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>
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>
>
>
>
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