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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Tue, 15 Mar 2022 13:22:42 +0100
Message-ID: <CAPDyKFosSVMOXtin149h=YaLeMEUq3Q0-xwYcg0ZgcfWRbawvA@mail.gmail.com>
Subject: Re: [PATCH] mmc: core: Improve fallback to speed modes if eMMC HS200 fails
To:     Heiner Kallweit <hkallweit1@gmail.com>
Cc:     linux-mmc@vger.kernel.org, Adrian Hunter <adrian.hunter@intel.com>,
        Wolfram Sang <wsa+renesas@sang-engineering.com>,
        Yann Gautier <yann.gautier@foss.st.com>,
        linux-kernel@vger.kernel.org
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On Mon, 14 Mar 2022 at 23:02, Heiner Kallweit <hkallweit1@gmail.com> wrote:
>
> On 14.03.2022 11:54, Ulf Hansson wrote:
> > On Thu, 3 Mar 2022 at 17:45, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> >>
> >> In the error path of mmc_select_hs200() we are trying our best to restore
> >> the card/host into a valid state. This makes sense, especially if we
> >> encounter a simple switch error (-EBADMSG). However, rather than then
> >> continue with using the legacy speed mode, let's try the other better speed
> >> modes first. Additionally, let's update the card->mmc_avail_type to avoid
> >> us from trying a broken HS200 mode again.
> >>
> >> In an Amlogic S905W based TV box where the switch to HS200 mode fails for
> >> the eMMC, this allows us to use the eMMC in DDR mode in favor of the legacy
> >> mode, which greatly improves the performance.
> >>
> >> Suggested-by: Heiner Kallweit <hkallweit1@gmail.com>
> >> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> >
> > Heiner, does this solve your problems? Can you perhaps run some tests
> > at your side to see how it works for you?
> >
>
> Tested-by: Heiner Kallweit <hkallweit1@gmail.com>

Thanks! Patch applied for next.

[...]

Kind regards
Uffe