Re: [PATCH v31 2/4] scsi: ufs: L2P map management for HPB read

[Can Guo]

On 2021-03-23 13:37, Daejun Park wrote:
> > On 2021-03-23 12:22, Can Guo wrote:
> > > On 2021-03-22 17:11, Bean Huo wrote:
> > > > On Mon, 2021-03-22 at 15:54 +0900, Daejun Park wrote:
> > > > > +       switch (rsp_field->hpb_op) {
> > > > >
> > > > > +       case HPB_RSP_REQ_REGION_UPDATE:
> > > > >
> > > > > +               if (data_seg_len != DEV_DATA_SEG_LEN)
> > > > >
> > > > > +                       dev_warn(&hpb->sdev_ufs_lu->sdev_dev,
> > > > >
> > > > > +                                "%s: data seg length is not
> > > > > same.\n",
> > > > >
> > > > > +                                __func__);
> > > > >
> > > > > +               ufshpb_rsp_req_region_update(hpb, rsp_field);
> > > > >
> > > > > +               break;
> > > > >
> > > > > +       case HPB_RSP_DEV_RESET:
> > > > >
> > > > > +               dev_warn(&hpb->sdev_ufs_lu->sdev_dev,
> > > > >
> > > > > +                        "UFS device lost HPB information during
> > > > > PM.\n");
> > > > >
> > > > > +               break;
> > > >
> > > > Hi Deajun,
> > > > This series looks good to me. Just here I have one question. You
> > > > didn't
> > > > handle HPB_RSP_DEV_RESET, just a warning.  Based on your SS UFS, how
> > > > to
> > > > handle HPB_RSP_DEV_RESET from the host side? Do you think we shoud
> > > > reset host side HPB entry as well or what else?
> > > >
> > > >
> > > > Bean
> > >
> > > Same question here - I am still collecting feedbacks from flash 
> > > vendors
> > > about
> > > what is recommanded host behavior on reception of HPB Op code 0x2,
> > > since it
> > > is not cleared defined in HPB2.0 specs.
> > >
> > > Can Guo.
> >
> > I think the question should be asked in the HPB2.0 patch, since in
> > HPB1.0 device
> > control mode, a HPB reset in device side does not impact anything in
> > host side -
> > host is not writing back any HPB entries to device anyways and HPB 
> > Read
> > cmd with
> > invalid HPB entries shall be treated as normal Read(10) cmd without 
> > any
> > problems.
>
> Yes, UFS device will process read command even the HPB entries are 
> valid or
> not. So it is warning about read performance drop by dev reset.

Yeah, but still I am 100% sure about what should host do in case of 
HPB2.0
when it receives HPB Op code 0x2, I am waiting for feedbacks.

Thanks,
Can Guo.

> Thanks,
> Daejun
>
> > Please correct me if I am wrong.
>
>
>
> > Thanks,
> > Can Guo.