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From:   Siarhei Volkau <lis8215@gmail.com>
Date:   Mon, 17 Oct 2022 20:29:27 +0300
Message-ID: <CAKNVLfY87P6jTG8g5L_S84MUXCfL1Z0GLgAdZqD4K6h6ubJb-Q@mail.gmail.com>
Subject: Re: [PATCH v2 2/2] dmaengine: JZ4780: Add support for the JZ4755.
To:     Paul Cercueil <paul@crapouillou.net>
Cc:     Vinod Koul <vkoul@kernel.org>, Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        dmaengine@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org
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=D0=BF=D0=BD, 17 =D0=BE=D0=BA=D1=82. 2022 =D0=B3. =D0=B2 12:34, Paul Cercue=
il <paul@crapouillou.net>:
> Can you verify that?
>
> It should be pretty simple, if it has the bug you'll see I/O errors on
> the SD card.

Well, the result is ambiguous:

Without that 'broken' flag: mmc works poorly, but becomes more or less
stable when MMC clock downs to 6MHz (90% boots without errors).
On the 12MHz MMC clock the issue doesn't appear in 50-70% cases.
On the 24MHz MMC clock the device never boots up.

However with the flag: MMC works stable on 24MHz MMC clock
(boot issue observed only once), but if I increase MMC clock speed even
a bit the problem appears oftenly ( >70% of cases).

So, that flag definitely helps a lot, but the nature of the problem might b=
e
different.

BR,
Siarhei