linux-kernel - RE: [PATCH v1] scsi: ufs-mediatek: Enable UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH

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Message-ID: <DM6PR04MB657598535F633F59A1DB1F22FCDE0@DM6PR04MB6575.namprd04.prod.outlook.com>
Date:   Wed, 23 Dec 2020 07:47:10 +0000
From:   Avri Altman <Avri.Altman@....com>
To:     Can Guo <cang@...eaurora.org>,
        Stanley Chu <stanley.chu@...iatek.com>
CC:     "linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
        "martin.petersen@...cle.com" <martin.petersen@...cle.com>,
        "alim.akhtar@...sung.com" <alim.akhtar@...sung.com>,
        "jejb@...ux.ibm.com" <jejb@...ux.ibm.com>,
        "beanhuo@...ron.com" <beanhuo@...ron.com>,
        "asutoshd@...eaurora.org" <asutoshd@...eaurora.org>,
        "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
        "bvanassche@....org" <bvanassche@....org>,
        "linux-mediatek@...ts.infradead.org" 
        <linux-mediatek@...ts.infradead.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "kuohong.wang@...iatek.com" <kuohong.wang@...iatek.com>,
        "peter.wang@...iatek.com" <peter.wang@...iatek.com>,
        "chun-hung.wu@...iatek.com" <chun-hung.wu@...iatek.com>,
        "andy.teng@...iatek.com" <andy.teng@...iatek.com>,
        "chaotian.jing@...iatek.com" <chaotian.jing@...iatek.com>,
        "cc.chou@...iatek.com" <cc.chou@...iatek.com>,
        "jiajie.hao@...iatek.com" <jiajie.hao@...iatek.com>,
        "alice.chao@...iatek.com" <alice.chao@...iatek.com>
Subject: RE: [PATCH v1] scsi: ufs-mediatek: Enable
 UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH_CTRL

> 
> On 2020-12-23 12:19, Stanley Chu wrote:
> > Hi Can,
> >
> > On Tue, 2020-12-22 at 19:34 +0800, Can Guo wrote:
> >> On 2020-12-22 15:29, Stanley Chu wrote:
> >> > Flush during hibern8 is sufficient on MediaTek platforms, thus
> >> > enable UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH_CTRL to skip
> enabling
> >> > fWriteBoosterBufferFlush during WriteBooster initialization.
> >> >
> >> > Signed-off-by: Stanley Chu <stanley.chu@...iatek.com>
> >> > ---
> >> >  drivers/scsi/ufs/ufs-mediatek.c | 1 +
> >> >  1 file changed, 1 insertion(+)
> >> >
> >> > diff --git a/drivers/scsi/ufs/ufs-mediatek.c
> >> > b/drivers/scsi/ufs/ufs-mediatek.c
> >> > index 80618af7c872..c55202b92a43 100644
> >> > --- a/drivers/scsi/ufs/ufs-mediatek.c
> >> > +++ b/drivers/scsi/ufs/ufs-mediatek.c
> >> > @@ -661,6 +661,7 @@ static int ufs_mtk_init(struct ufs_hba *hba)
> >> >
> >> >    /* Enable WriteBooster */
> >> >    hba->caps |= UFSHCD_CAP_WB_EN;
> >> > +  hba->quirks |= UFSHCI_QUIRK_SKIP_MANUAL_WB_FLUSH_CTRL;
> >> >    hba->vps->wb_flush_threshold =
> UFS_WB_BUF_REMAIN_PERCENT(80);
> >> >
> >> >    if (host->caps & UFS_MTK_CAP_DISABLE_AH8)
> >>
> >> I guess we need it too...
> >
> > AHHA, if you decide to add this in your platform too later, maybe we
> > could change the way it does: Keep manual flush disabled by default and
> > remove this quirk.
Ack on that.
I never understood why it was needed in the first place.
Maybe just remove it, and allow to perform explicit flush from sysfs.

Thanks,
Avri
> >
> 
> Yeah... I will get back with an answer later.