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Subject: Re: [PATCH] mmc: host: sdhci: Fix the incorrect soft reset operation
 when runtime resuming
To:     Baolin Wang <baolin.wang@linaro.org>, ulf.hansson@linaro.org
Cc:     zhang.lyra@gmail.com, orsonzhai@gmail.com,
        linus.walleij@linaro.org, vincent.guittot@linaro.org,
        linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org
References: <4c5812f54e5094fa54a85bdc86687a523df254b3.1563184923.git.baolin.wang@linaro.org>
From:   Adrian Hunter <adrian.hunter@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki,
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Message-ID: <c54077a4-3aae-c95c-8491-db5f05b0305c@intel.com>
Date:   Mon, 15 Jul 2019 14:19:35 +0300
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On 15/07/19 1:58 PM, Baolin Wang wrote:
> In sdhci_runtime_resume_host() function, we will always do software reset
> for all, but according to the specification, we should issue reset command
> and reinitialize the SD/eMMC card.

Where does it say that?

>                                    However, we only do reinitialize the
> SD/eMMC card when the SD/eMMC card are power down during runtime suspend.
> 
> Thus for those platforms that do not power down the SD/eMMC card during
> runtime suspend, we should not do software reset for all.
>                                                           To fix this
> issue, we can add one condition to validate the MMC_CAP_AGGRESSIVE_PM
> to decide if we can do software reset for all or just reset command
> and data lines.
> 
> Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
> ---
>  drivers/mmc/host/sdhci.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 9715834..470c5e0 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -3333,7 +3333,7 @@ int sdhci_runtime_resume_host(struct sdhci_host *host)
>  			host->ops->enable_dma(host);
>  	}
>  
> -	sdhci_init(host, 0);
> +	sdhci_init(host, !(mmc->caps & MMC_CAP_AGGRESSIVE_PM));

We have done a full reset for a long time, so it would be surprising to need
to change it.

What problem is it causing?

>  
>  	if (mmc->ios.power_mode != MMC_POWER_UNDEFINED &&
>  	    mmc->ios.power_mode != MMC_POWER_OFF) {
>