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Subject: Re: [PATCH v6] arm64: dts: rockchip: Fix SD card init on
 rk3399-nanopi4
Date:   Mon, 18 Jul 2022 23:04:43 +0200
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To:     Robin Murphy <robin.murphy@arm.com>, wens@kernel.org,
        =?utf-8?Q?Heiko_St=C3=BCbner?= <heiko@sntech.de>,
        Markus Reichl <m.reichl@fivetechno.de>,
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        linux-kernel <linux-kernel@vger.kernel.org>,
        Linux MMC List <linux-mmc@vger.kernel.org>
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Am 18.07.2022 um 14:05 schrieb Christian Kohlsch=C3=BCtter =
<christian@kohlschutter.com>:
>=20
>> Am 18.07.2022 um 14:04 schrieb Christian Kohlsch=C3=BCtter =
<christian@kohlschutter.com>:
>>=20
>> mmc/SD-card initialization may fail on NanoPi R4S with
>> "mmc1: problem reading SD Status register" /
>> "mmc1: error -110 whilst initialising SD card"
>> either on cold boot or after a reboot.
> ...
> Walking back on my claim in the commit message that no further patches =
are needed for the u-boot integration to work.
> Other than that, the actual patch is unchanged.

I can no longer verify that the v6 patch actually increases use_count to =
2.

At this point, I don't have a purely device tree-based fix that works =
reliably, therefore necessitating the code changes in regulator/core.c.
If anyone of you knows a way to reliably increase vcc3v0_sd's use_count =
("cat /sys/kernel/debug/regulator/vcc3v0_sd/use_count") to at least 2, =
then we can remove the regulator-always-on statement.