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Date: Wed, 3 Mar 2021 20:29:25 +0900
From: "DooHyun Hwang" <dh0421.hwang@...sung.com>
To: "'Ulf Hansson'" <ulf.hansson@...aro.org>
Cc: <linux-mmc@...r.kernel.org>,
"'Linux Kernel Mailing List'" <linux-kernel@...r.kernel.org>,
"'Eric Biggers'" <ebiggers@...gle.com>,
"'Wolfram Sang'" <wsa+renesas@...g-engineering.com>,
"'Satya Tangirala'" <satyat@...gle.com>,
"'Ludovic Barre'" <ludovic.barre@...com>,
"'Linus Walleij'" <linus.walleij@...aro.org>,
<grant.jung@...sung.com>, <jt77.jang@...sung.com>,
<junwoo80.lee@...sung.com>, <jangsub.yi@...sung.com>,
"'Seunghui Lee'" <sh043.lee@...sung.com>,
"'Chanwoo Lee'" <cw9316.lee@...sung.com>,
<sh8267.baek@...sung.com>, <wkon.kim@...sung.com>
Subject: RE: [PATCH] mmc: core: add a power cycle when CMD11 fails
On Wed, 3 Mar 2021 at 12:00, Ulf Hansson <ulf.hansson@...aro.org> wrote:
>
>On Wed, 3 Mar 2021 at 07:30, DooHyun Hwang <dh0421.hwang@...sung.com> wrote:
>>
>> On Tue, 2 Mar 2021 at 10:38, Ulf Hansson <ulf.hansson@...aro.org> wrote:
>> >On Wed, 10 Feb 2021 at 06:12, DooHyun Hwang
>> ><dh0421.hwang@...sung.com>
>> >wrote:
>> >>
>> >> A power cycle is required if CMD11 fails.
>> >> CMD11 failure should be handled as no response.
>> >>
>> >> If there is a timeout error that means no response to the CMD11, do
>> >> not send the CMD11 again and the power cycle is required.
>> >> Any other errors for CMD11 are the same because CMD11 failed.
>> >>
>> >> On some bad SD Card, CMD11 may fail but the card may have already
>> >> invoked the voltage switch sequence.
>> >> In this case, it is necessary to retry without voltage switching
>> >> after power cycle.
>> >>
>> >> Signed-off-by: DooHyun Hwang <dh0421.hwang@...sung.com>
>> >
>> >Applied for next, thanks!
>> >
>> >I took the liberty of updating the commit message a bit, to try to
>> >clarify things. Moreover, I have tagged this for stable kernels.
>> >
>> >BTW, did you try to force the error to -EAGAIN, to keep retrying for
>> >a couple of times? If so, did it end up with the same kind of errors?
>>
>> Thank you for reviewing this.
>>
>> Yes. I tested with 2 SD cards.
>> I think the power cycle is needed before retrying because SD card
>> doesn't respond SD_ROCR_S18A when retrying without power cycle.
>
>Thanks for sharing the logs and the details below!
>
>If I understand correctly, forcing the error to -EAGAIN combined with the
>power cycle when the CMD11 fails, actually makes us succeed with the
>voltage switch in the second retry. Correct?
Yes, That's right.
>
>In that case, it seems like a good idea to extend $subject patch to return
>-EAGAIN in case we get an error from the CMD11, right?
Yes, I think so.
But it looks good to retry CMD11 only for a couple of times, and if it still fails,
it would be better to remove SD_OCR_S18R and retry ACMD41 as before.
>
>[...]
>
>>
>> #4. SD card responded with SD_ROCR_S18A from ACMD41 after power cycle,
>> and change CMD11's error value to -EAGAIN // send ACMD41 + with
>SD_OCR_S18R (bit[24])
>> <7>[ 156.884623] [0: kworker/0:1: 7] mmc0: starting CMD41 arg
>51040000 flags 000000e1
>> // resp ACMD41 + with SD_ROCR_S18A (bit[24])
>> <7>[ 156.884975] I[0: highpool[3]: 5440] mmc0: req done (CMD41): 0:
>c1ff8000 00000000 00000000 00000000
>> // send CMD11 and error occurs
>> <7>[ 156.885051] [0: kworker/0:1: 7] mmc0: starting CMD11 arg
>00000000 flags 00000015
>> <7>[ 156.885759] I[0: highpool[3]: 5440] mmc0: req done (CMD11): -84:
>00000000 00000000 00000000 00000000
>> // retry with power cycle (tested with this patch)
>> <7>[ 156.885834] [0: kworker/0:1: 7] mmc0: Signal voltage switch
>failed, power cycling card
>> <7>[ 156.885875] [0: kworker/0:1: 7] mmc0: clock 0Hz busmode 2
>powermode 0 cs 0 Vdd 0 width 1 timing 0
>> <7>[ 156.920185] [0: kworker/0:1: 7] mmc0: clock 400000Hz busmode 2
>powermode 2 cs 0 Vdd 18 width 1 timing 0
>> // change CMD11's error value to -EAGAIN
>> <3>[ 156.932288] [0: kworker/0:1: 7] mmc_sd_get_cid: rocr=0xc1ff8000,
>retries=10. err=-84 -> -11.
>> <7>[ 156.932336] [0: kworker/0:1: 7] mmc0: clock 400000Hz busmode 2
>powermode 2 cs 1 Vdd 18 width 1 timing 0
>> <7>[ 156.933834] [0: kworker/0:1: 7] mmc0: starting CMD0 arg
>00000000 flags 000000c0
>> <7>[ 156.934101] I[0:ung.android.mdx:10229] mmc0: req done (CMD0): 0:
>00000000 00000000 00000000 00000000
>> <7>[ 156.935562] [0: kworker/0:1: 7] mmc0: clock 400000Hz busmode 2
>powermode 2 cs 0 Vdd 18 width 1 timing 0
>> <7>[ 156.937009] [0: kworker/0:1: 7] mmc0: starting CMD8 arg
>000001aa flags 000002f5
>> <7>[ 156.937372] I[0:ung.android.mdx:10229] mmc0: req done (CMD8): 0:
>> 000001aa 00000000 00000000 00000000 // send ACMD41 + with SD_OCR_S18R
>(bit[24])
>> <7>[ 157.044190] [0: kworker/0:1: 7] mmc0: starting CMD55 arg
>00000000 flags 000000f5
>> <7>[ 157.044924] I[0:ung.android.mdx:10229] mmc0: req done (CMD55): 0:
>00000120 00000000 00000000 00000000
>> <7>[ 157.045023] [0: kworker/0:1: 7] mmc0: starting CMD41 arg
>51040000 flags 000000e1
>> // resp ACMD41 + with SD_ROCR_S18A (bit[24]) <7>[ 157.045389]
>> I[0:ung.android.mdx:10229] mmc0: req done (CMD41): 0: c1ff8000
>> 00000000 00000000 00000000 // send CMD11 and complete
>> <7>[ 157.045467] [0: kworker/0:1: 7] mmc0: starting CMD11 arg
>00000000 flags 00000015
>> <7>[ 157.045855] I[0: Binder:798_2: 805] mmc0: req done (CMD11): 0:
>00000320 00000000 00000000 00000000
>>
>>
>> >
>> >> ---
>> >> drivers/mmc/core/core.c | 2 +-
>> >> 1 file changed, 1 insertion(+), 1 deletion(-)
>> >>
>> >> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>> >> index 1136b859ddd8..a6674df2a7bb 100644
>> >> --- a/drivers/mmc/core/core.c
>> >> +++ b/drivers/mmc/core/core.c
>> >> @@ -1207,7 +1207,7 @@ int mmc_set_uhs_voltage(struct mmc_host
>> >> *host,
>> >> u32 ocr)
>> >>
>> >> err = mmc_wait_for_cmd(host, &cmd, 0);
>> >> if (err)
>> >> - return err;
>> >> + goto power_cycle;
>> >>
>> >> if (!mmc_host_is_spi(host) && (cmd.resp[0] & R1_ERROR))
>> >> return -EIO;
>> >> --
>> >> 2.29.0
>> >>
>
>Kind regards
>Uffe
Thanks and regards.
DooHyun Hwang.
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