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From:   Avri Altman <Avri.Altman@wdc.com>
To:     Michael Wu <michael@allwinnertech.com>,
        "maintainer:MULTIMEDIA CARD (MMC), SECURE DIGITAL (SD) AND... 
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CC:     Ulf Hansson <ulf.hansson@linaro.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Luca Porzio <porzio@gmail.com>,
        lixiang <lixiang@allwinnertech.com>,
        Bean Huo <beanhuo@micron.com>,
        "open list:MULTIMEDIA CARD (MMC), SECURE DIGITAL (SD) AND..." 
        <linux-mmc@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] mmc: block: enable cache-flushing when mmc cache is on
Thread-Topic: [PATCH] mmc: block: enable cache-flushing when mmc cache is on
Thread-Index: AQHYNcu0Jgralp1XlUCNRLBRM2Fhq6y+fT5Q
Date:   Mon, 14 Mar 2022 07:26:26 +0000
Message-ID: <DM6PR04MB6575D203B92955D9A913576CFC0F9@DM6PR04MB6575.namprd04.prod.outlook.com>
References: <20220312044315.7994-1-michael@allwinnertech.com>
In-Reply-To: <20220312044315.7994-1-michael@allwinnertech.com>
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Hi,
> The mmc core enable cache on default. But it only enables cache-flushing
> when host supports cmd23 and eMMC supports reliable write.
> For hosts which do not support cmd23 or eMMCs which do not support
> reliable write, the cache can not be flushed by `sync` command.
> This may leads to cache data lost.
> This patch enables cache-flushing as long as cache is enabled, no matter =
host
> supports cmd23 and/or eMMC supports reliable write or not.
I looked in the spec and indeed couldn't find why enabling cache is depende=
nt of cmd23/reliable write.
Nor I was able to find the original commit log.

Please allow few days to ask internally.

Thanks,
Avri