Re: [PATCH] mmc: sd: Add a variable to check a faulty device

[Christian Loehle]

On 13/02/2024 09:49, 이승희 wrote:
> 
> 
>> -----Original Message-----
>> From: Avri Altman <Avri.Altman@xxxxxxx>
>> Sent: Tuesday, February 13, 2024 5:42 PM
>> To: Seunghui Lee <sh043.lee@xxxxxxxxxxx>; linux-mmc@xxxxxxxxxxxxxxx;
>> linux-kernel@xxxxxxxxxxxxxxx; ulf.hansson@xxxxxxxxxx;
>> gregkh@xxxxxxxxxxxxxxxxxxx
>> Cc: grant.jung@xxxxxxxxxxx; jt77.jang@xxxxxxxxxxx;
>> dh0421.hwang@xxxxxxxxxxx; junwoo80.lee@xxxxxxxxxxx; jangsub.yi@xxxxxxxxxxx;
>> cw9316.lee@xxxxxxxxxxx; sh8267.baek@xxxxxxxxxxx; wkon.kim@xxxxxxxxxxx
>> Subject: RE: [PATCH] mmc: sd: Add a variable to check a faulty device
>>
>>> In mobile devices, suspend/resume situations are frequent.
>>> In the case of a defective SD card in which initialization fails,
>>> unnecessary initialization time is consumed for each resume.
>>> A field is needed to check that SD card initialization has failed on
>>> the host. It could be used to remove unnecessary initialization.
>> I don't see where you are using this new init_failed field?
>> Maybe instead, elaborate the logic to free_card: to detect a broken sd.
>> e.g. instead of just if (!oldcard), if (!oldcard || ! mmc_sd_alive(host))
>> or something.
>>
>> Thanks,
>> Avri
>>
> Thank you for your suggestion.
> I'm going to use it in mmc_rescan as below.
> 
> e.g.
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index a8c17b4cd737..461cd75dc7ab 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -2210,7 +2210,7 @@ void mmc_rescan(struct work_struct *work)
>                 container_of(work, struct mmc_host, detect.work);
>         int i;
>  
> -       if (host->rescan_disable)
> +       if (host->rescan_disable || host->init_failed)
>                 return;

I've seen SD cards that fail the first initialization attempt for both
'valid' reasons (e.g. weird insertion timing) and things like out-of-spec
initialization time from the card, outright disabling these on the first
fail is a bit too much IMO.

Kind Regards,
Christian