Odroid-C1 regression with commit 4bc31edebde5 ("mmc: core: Set HS clock speed before sending HS CMD13")

[Linux regression tracking (Thorsten Leemhuis)]

Hi, Thorsten here, the Linux kernel's regression tracker. Top-posting
for once, to make this easily accessible to everyone.

Ulf, Martin, what happened to this? It looks like we didn't get any
closer to fixing this regression in the last two weeks. Did it fall
through the cracks? Or was progress made and I just missed it?

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
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#regzbot poke

On 16.05.23 22:45, Martin Blumenstingl wrote:
> On Mon, May 15, 2023 at 11:44 AM Ulf Hansson <ulf.hansson at linaro.org> wrote:
> [...]
>>>> 3) If 2) seems to work above, we need to figure out why
>>>> mmc_switch_status() is hanging. If there is a problem with the eMMC
>>>> card responding in-correctly, the host driver should return with an
>>>> error code, right?
>>> You're right: it's indeed hanging in mmc_switch_status()
>>> I don't get any interrupts (timeout, CRC error, ...) for it.
>>> Do you have any suggestions what to check next?
>>
>> So the mmc_switch_status() is sending a CMD13. Even if the card
>> doesn't reply, I would expect that the meson mmc controller would
>> raise some kind of error condition, probably via a timeout-irq.
>>
>> Did you verify that the driver is actually waiting for an IRQ to
>> happen, which also means waiting for a CMD13 response?
> register 0x24 is ICTL (interrupt control) and 0x28 is ISTAT (interrupt status)
> ISTAT is all zeros and ICTL is 0x3067 which translates so:
> - BIT(0): RESP_OK
> - BIT(1): RESP_TIMEOUT
> - BIT(2): RESP_ERR_CRC
> - BIT(5): DATA_TIMEOUT
> - BIT(6): DATA_ERR_CRC
> - BIT(12): RXFIFO_FULL
> - BIT(13): TXFIFO_EMPTY
> 
> I guess in this case BIT(1) RESP_TIMEOUT is the relevant one.
> 
> register 0x04 is SEND and reads 0x4d which translates to:
> - CMD13
> - MMC_RSP_PRESENT (HAS_RESP, BIT(6))
> - no other flags (STOP, R1B, ...) are set
> 
> Full register dump:
> # cat /sys/kernel/debug/regmap/c1108e00.mmc/registers
> 00: 00000900
> 04: 0000004d
> 08: e7ffe002
> 0c: 02f0003f
> 10: 0003f009
> 14: 03b81c00
> 18: 2c43bcf0
> 1c: e0000150
> 20: 00000000
> 24: 00003067
> 28: 00000000
> 2c: 00000000
> 30: 00000000
> 34: 00fe0cff
> 38: 0000100b
> 
> In case you are curious, the driver is: drivers/mmc/host/meson-mx-sdhc-mmc.c
> 
> 
> Best regards,
> Martin