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From:   Avri Altman <Avri.Altman@wdc.com>
To:     Jaegeuk Kim <jaegeuk@kernel.org>
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        "martin.petersen@oracle.com" <martin.petersen@oracle.com>,
        "stanley.chu@mediatek.com" <stanley.chu@mediatek.com>
Subject: RE: [PATCH] scsi: ufs: fix livelock of ufshcd_clear_ua_wluns
Thread-Topic: [PATCH] scsi: ufs: fix livelock of ufshcd_clear_ua_wluns
Thread-Index: AQHW1O5Lq9Xt0bukCk2VnSNzzSWPAqoAjHbQgAEkMYCAABqVAIAABd2AgAAK2YCAABsmAIAACjhw
Date:   Mon, 21 Dec 2020 20:13:59 +0000
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> > > > > > > In order to avoid it, ufshcd_clear_ua_wluns() can be called p=
er
> > > recovery
> > > > > > > flows
> > > > > > > such as suspend/resume, link_recovery, and error_handler.
> > > > > > Not sure that suspend/resume are UAC events?
> > > > >
> > > > > Could you elaborate a bit? The goal is to clear UAC after UFS res=
et
> > > happens.
> > > > So why calling it on every suspend and resume?
> > >
> > > 1. If UAC was cleared, there's no impact.
> > But the command is still sent.
>=20
> No, ufshcd_clear_ua_wluns() will return by hba->wlun_dev_clr_ua.
>=20
> >
> > > 2. ufshcd_link_recovery() can reset UFS directly by ufs_mtk_resume().
> > > 3. ufshcd_suspend can call ufshcd_host_reset_and_restore() as well.
> > Seems excessive IMO.
> > Why not selectively send when indeed required, e.g. on reset?
>=20
> I think hba->wlun_dev_clr_ua is the indicator whether there was a reset o=
r
> not.
Ahha - I missed that.  Thanks for clarifying it.
OK Then.

Thanks,
Avri