Question about ACMD42

Question about ACMD42

[梁亦飞]

Hi ,
     This might be a stupid question, in  <<Physical Layer Simplified
Specification Version 2.00>>,there is a command SET_CLR_CARD_
DETECT, as spec discribed Connect[1]/Disconnect[0] the 50 KOhm pull-up
resistor on CD/DAT3 (pin 1) of
the card.
     If this command is use to switch the card beteewn the DAT[3] and
CD mode, why i don't see it's being
use in kernel. Under what circumstance we should use this command?

Regards

Re: Question about ACMD42

[Michał Mirosław]

2010/9/3 梁亦飞 <dinuxlyf@gmail.com>:
> Hi ,
>     This might be a stupid question, in  <<Physical Layer Simplified
> Specification Version 2.00>>,there is a command SET_CLR_CARD_
> DETECT, as spec discribed Connect[1]/Disconnect[0] the 50 KOhm pull-up
> resistor on CD/DAT3 (pin 1) of
> the card.
>     If this command is use to switch the card beteewn the DAT[3] and
> CD mode, why i don't see it's being
> use in kernel. Under what circumstance we should use this command?

The pullup is disabled for SDIO part, but not for memory part. I would
call it a bug. This should go to mmc_sd_setup_card() in sd.c. I'll
send a fix after I get my dev machine up, unless someone beats me to
it.

Best Regards,
Michał Mirosław