Re: [PATCH v3 5/6] scsi: ufshpb: Add handing of device reset HPB regions Infos in HPB device mode

From: Bean Huo
Date: Tue Apr 26 2022 - 17:54:51 EST

On Mon, 2022-04-25 at 06:43 +0000, Avri Altman wrote:
> >
> > Therefore, for HPB device control mode, if the UFS device is reset
> > via the
> > RST_N
> > pin, the active region information in the device will be reset. If
> > the host side
> > receives this notification from the device side, it is recommended
> > to inactivate
> > all active regions in the host's HPB cache.
> While it makes sense to me, this interpretation of the spec takes
> extreme action,
> Compared to what it is today, and you probably need to get an ack
> from Daejun.

Yes, but it seems he is quiet. Keoseong Park is on the email list and
he has looked at the patch. If you have concerns, I can ping Keoseong
Park to sync with Daejun.

> If we are entering a zone in which each vendor is applying a
> different logic -
> I think you need to facilitate that - maybe in a different patch set.

Yes, it should be a different patch. I must say that this patch is
based on the HPB Spec, say, if the device loses HPB info. The host side
should also reset its HPB information, Otherwise, performance will
degrade. Of course, it depends on the specific implementation of the
vendor. If they don't report 02:HPB operations, this patch still
doesn't change the original behavior.

Kind regards,