内核在引导的过程中，出现了如下的关于SD卡的提示：
s3c-sdi s3c2440-sdi: powered down.
s3c-sdi s3c2440-sdi: mmc0 - using pio, sw SDIO IRQ
但是没有出现类似于如下的提示：
s3c-sdi s3c2440-sdi: running at 0kHz (requested: 0kHz).
s3c-sdi s3c2440-sdi: running at 400kHz (requested: 400kHz).
s3c-sdi s3c2440-sdi: running at 400kHz (requested: 400kHz).
s3c-sdi s3c2440-sdi: running at 400kHz (requested: 400kHz).
s3c-sdi s3c2440-sdi: running at 400kHz (requested: 400kHz).
s3c-sdi s3c2440-sdi: running at 400kHz (requested: 400kHz).
s3c-sdi s3c2440-sdi: running at 400kHz (requested: 400kHz).
s3c-sdi s3c2440-sdi: running at 400kHz (requested: 400kHz).
s3c-sdi s3c2440-sdi: running at 25000kHz (requested: 25000kHz).
s3c-sdi s3c2440-sdi: running at 25000kHz (requested: 25000kHz).
mmc0: new SD card at address eb14
mmcblk0: mmc0:eb14 SD02G 1.83 GiB
mmcblk0: p1 p2
这个是什么原因呢？
