Re: [PATCH] mmc: fixed wrong SD card detection

[Jaehoon Chung <jh80.chung@samsung.com>]

Hi Chris..

Chris Ball wrote:
> Hi Jaehoon,
> 
> On Fri, May 06 2011, Jaehoon Chung wrote:
>> This patch added mmc_power_off after mmc_attach_sd()
>>
>> i found that didn't detect the second card insert.(using SDHCI)
>> you can see the below log.
>>
>> i want to know that somebody know this issue...
>>
>> ->first card inserted (correct card detect)
>> # mmc1: new SDHC card at address e624
>> mmcblk1: mmc1:e624 SU04G 3.69 GiB
>>  mmcblk1: p1
>> #
>> # mmc1: card e624 removed
>> -> second card inserted
>> mmc1: error -110 whilst initialising SD card
>> mmc1: Card removed during transfer!
>> mmc1: Resetting controller.
>> -> third card inserted 
>> mmc1: new SDHC card at address e624
>> mmcblk1: mmc1:e624 SU04G 3.69 GiB
>>  mmcblk1: p1
>>
>> I added mmc_power_off() after only mmc_attach_sd().
>>
>> Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
>> Signed-off-by: kyungmin Park <kyungmin.park@samsung.com>
>> ---
>>  drivers/mmc/core/core.c |    4 +++-
>>  1 files changed, 3 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>> index 1dbc185..d5d8ac0 100644
>> --- a/drivers/mmc/core/core.c
>> +++ b/drivers/mmc/core/core.c
>> @@ -1522,8 +1522,10 @@ static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
>>  	/* Order's important: probe SDIO, then SD, then MMC */
>>  	if (!mmc_attach_sdio(host))
>>  		return 0;
>> -	if (!mmc_attach_sd(host))
>> +	if (!mmc_attach_sd(host)) {
>> +		mmc_power_off(host);
>>  		return 0;
>> +	}
>>  	if (!mmc_attach_mmc(host))
>>  		return 0;
>>  
> 
> It looks to me like this patch says "if we successfully attach/power up
> an SD card, then power it back off again immediately".  Why would that
> make sense?

It's non-sense...i know...How did you think about that problem..?
I want to get your advise...

> 
> - Chris.