RE: [PATCH] scsi: ufs: fix livelock of ufshcd_clear_ua_wluns

From: Avri Altman
Date: Mon Dec 21 2020 - 15:15:09 EST


> > > > > > > In order to avoid it, ufshcd_clear_ua_wluns() can be called per
> > > 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 reset
> > > 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.
>
> No, ufshcd_clear_ua_wluns() will return by hba->wlun_dev_clr_ua.
>
> >
> > > 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?
>
> I think hba->wlun_dev_clr_ua is the indicator whether there was a reset or
> not.
Ahha - I missed that. Thanks for clarifying it.
OK Then.

Thanks,
Avri