From: Adrian Hunter <adrian.hunter@intel.com>
To: Ulf Hansson <ulf.hansson@linaro.org>, "Y.b. Lu" <yangbo.lu@nxp.com>
Cc: "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
Sachin Miglani <sachin.miglani@nxp.com>
Subject: Re: [PATCH] mmc: sdhci: fix up CMD12 sending
Date: Fri, 17 Jan 2020 16:15:13 +0200 [thread overview]
Message-ID: <88442ced-8bf0-5f29-ad47-cc53162f157b@intel.com> (raw)
In-Reply-To: <CAPDyKFq7VnfYAs=RcjUpskAfSC_fatksQ1_sJ6wEOinbPDKmkQ@mail.gmail.com>
On 16/01/20 5:36 pm, Ulf Hansson wrote:
> On Wed, 8 Jan 2020 at 10:37, Y.b. Lu <yangbo.lu@nxp.com> wrote:
>>
>> Hi Uffe and Adrian,
>>
>> Back again on this topic. Actually we are trying to make the error recovery work after data error of CMD18 in linux-4.14.
>> With this patch, when CMD18 data error got, manual CMD12 would be sent. And then went into mmc_blk_cmd_recovery(). (Should be mmc_blk_mq_rw_recovery() in latest linux-5.5-rc2.)
>> In mmc_blk_cmd_recovery(), re-tuning would fail before sending CMD13 on our specific board.
>> This may be some issue related to specific eMMC card we are investigating.
>>
>> The above is just background introduction, and you may not care about that:)
>> I'd like to have some queries on CMD12 usage in MMC driver.
>> 1. It seems CMD12 is always not using ABORT type for sending in sdhci.c. The SDHCI_CMD_ABORTCMD hasn't been used. Is this issue?
>
AFAIK it is not an issue, but support for it can be added if you need it.
>
>> 2. In block.c, CMD12 uses R1 response for data reading and R1B response for writing. Is it ok to use R1 response for SD? The SD spec mentions only R1B response for CMD12.
>
> I think the specs isn't that clear on this. In this case, the R1B, is
> an R1 with an *optional* busy signaling on DAT0, unless it has been
> changed lately.
Also SDHCI offers SDHCI_QUIRK2_STOP_WITH_TC to turn all CMD12 responses into R1B
>
> Additionally, as far as can tell, there have been no reports about
> problems with the current approach for "reads". Are you saying there
> is?
>
> [...]
>
> Kind regards
> Uffe
>
prev parent reply other threads:[~2020-01-17 14:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20191114111814.35199-1-yangbo.lu@nxp.com>
2019-11-29 9:17 ` [PATCH] mmc: sdhci: fix up CMD12 sending Adrian Hunter
2019-12-10 9:51 ` Ulf Hansson
2020-01-08 9:37 ` Y.b. Lu
2020-01-16 15:36 ` Ulf Hansson
2020-01-17 14:15 ` Adrian Hunter [this message]
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