From: Avri Altman <Avri.Altman@wdc.com>
To: Bean Huo <huobean@gmail.com>,
"alim.akhtar@samsung.com" <alim.akhtar@samsung.com>,
"asutoshd@codeaurora.org" <asutoshd@codeaurora.org>,
"jejb@linux.ibm.com" <jejb@linux.ibm.com>,
"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
"stanley.chu@mediatek.com" <stanley.chu@mediatek.com>,
"beanhuo@micron.com" <beanhuo@micron.com>,
"bvanassche@acm.org" <bvanassche@acm.org>,
"tomas.winkler@intel.com" <tomas.winkler@intel.com>,
"cang@codeaurora.org" <cang@codeaurora.org>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v3 2/3] scsi: ufs: Keep device active mode only fWriteBoosterBufferFlushDuringHibernate == 1
Date: Thu, 10 Dec 2020 07:46:25 +0000 [thread overview]
Message-ID: <DM6PR04MB657504D6828919BAB731B16DFCCB0@DM6PR04MB6575.namprd04.prod.outlook.com> (raw)
In-Reply-To: <c95e0518fd5c73dead0139054c04dda2243af620.camel@gmail.com>
> On Wed, 2020-12-09 at 07:40 +0000, Avri Altman wrote:
> > > According to the JEDEC UFS 3.1 Spec, If
> > > fWriteBoosterBufferFlushDuringHibernate
> > > is set to one, the device flushes the WriteBooster Buffer data
> > > automatically
> > > whenever the link enters the hibernate (HIBERN8) state. While the
> > > flushing
> > > operation is in progress, the device should be kept in Active power
> > > mode.
> > > Currently, we set this flag during the UFSHCD probe stage, but we
> > > didn't deal
> > > with its programming failure. Even this failure is less likely to
> > > occur, but
> > > still it is possible.
> >
> > How about reading it on every ufshcd_wb_need_flush?
> >
> > Thanks,
> > Avri
>
>
> Hi Avri
> I was using that way, no different from the current my way. Instead,
> reading on every time will add some delay. As long as the UFS device
> returns the successful, we assume that this flag has been properly
> set. so, just keeping is_hibern8_wb_flush if set, I think it is
> enough.
Right.
But it is a small price, and you no longer need to worry about rare error event.
Also adding an if (fWriteBoosterBufferFlushDuringHibernate == 1) will allow some more flexibility,
e.g. shutting it off from user-space (ufs-utils), unlike today,
that it is categorically on for all platforms / devices.
Anyway, if you decided to add new capability,
Preferable to do it in a different series.
Thanks,
Avri
next prev parent reply other threads:[~2020-12-10 7:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-08 21:09 [PATCH v3 0/3] Three changes for UFS WriteBooster Bean Huo
2020-12-08 21:09 ` [PATCH v3 1/3] scsi: ufs: Add "wb_on" sysfs node to control WB on/off Bean Huo
2020-12-08 21:09 ` [PATCH v3 2/3] scsi: ufs: Keep device active mode only fWriteBoosterBufferFlushDuringHibernate == 1 Bean Huo
2020-12-09 7:40 ` Avri Altman
2020-12-09 22:03 ` Bean Huo
2020-12-10 7:46 ` Avri Altman [this message]
2020-12-10 20:13 ` Bean Huo
2020-12-09 22:08 ` Bean Huo
2020-12-08 21:09 ` [PATCH v3 3/3] scsi: ufs: Changes comment in the function ufshcd_wb_probe() Bean Huo
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