你们这个问题有没有解决？我也碰到这样的问题！
通过串口，输出的信息如下：
[ 295.694211] mmc0: new high speed SD card at address 0007
[ 295.697945] mmcblk0: mmc0:0007 SM02G 1.86 GiB
[ 295.700163] mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card status 0x0
[ 295.700242] mmcblk0: retrying using single block read
[ 295.700357] mmcblk0: timed out sending r/w cmd command, card status 0x400b00
[ 295.702922] mmcblk0: command error, retrying timeout
[ 295.710867] mmcblk0: error -84 transferring data, sector 1, nr 7, cmd response 0x900, card status 0x0
[ 295.717042] end_request: I/O error, dev mmcblk0, sector 1
[ 295.729361] Buffer I/O error on device mmcblk0, logical block 0
[ 295.730234] mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card status 0x0
[ 295.739732] mmcblk0: retrying using single block read
[ 295.742555] mmcblk0: error -84 sending status command, retrying
[ 295.752310] mmcblk0: timed out sending r/w cmd command, card status 0xb00
[ 295.755149] mmcblk0: status not valid, retrying timeout
[ 295.765549] mmcblk0: error -84 transferring data, sector 1, nr 7, cmd response 0x900, card status 0x0
[ 295.769667] end_request: I/O error, dev mmcblk0, sector 1
[ 295.776635] mmcblk0: error -84 transferring data, sector 2, nr 6, cmd response 0x900, card status 0x0
[ 295.787426] end_request: I/O error, dev mmcblk0, sector 2
[ 295.793037] Buffer I/O error on device mmcblk0, logical block 0
[ 295.796136] mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card status 0x0
[ 295.804867] mmcblk0: retrying using single block read
[ 295.810906] mmcblk0: error -84 sending status command, retrying
[ 295.818675] mmcblk0: error -84 sending status command, retrying
[ 295.821395] mmcblk0: timed out sending r/w cmd command, card status 0xb00
[ 295.830392] mmcblk0: status not valid, retrying timeout
[ 295.834939] mmcblk0: error -84 transferring data, sector 1, nr 7, cmd response 0x900, card status 0x0
[ 295.844689] end_request: I/O error, dev mmcblk0, sector 1
[ 295.848794] mmcblk0: error -84 transferring data, sector 2, nr 6, cmd response 0x900, card status 0x0
[ 295.857739] end_request: I/O error, dev mmcblk0, sector 2
[ 295.863395] mmcblk0: error -84 transferring data, sector 3, nr 5, cmd response 0x900, card status 0x0
[ 295.873365] end_request: I/O error, dev mmcblk0, sector 3
[ 295.879893] Buffer I/O error on device mmcblk0, logical block 0
[ 295.882907] mmcblk0: unable to read partition table
[ 295.911550] mmcblk0: error -84 transferring data, sector 0, nr 32, cmd response 0x900, card status 0x0
[ 295.911637] mmcblk0: retrying using single block read
[ 295.911733] mmcblk0: error -110 sending status command, retrying
[ 295.911823] mmcblk0: timed out sending r/w cmd command, card status 0x800b00
[ 295.916650] mmcblk0: status not valid, retrying timeout
[ 295.922698] mmc0: ADMA error
[ 295.924692] mmcblk0: error -5 transferring data, sector 0, nr 32, cmd response 0x900, card status 0x0
[ 295.935868] end_request: I/O error, dev mmcblk0, sector 0
[ 295.940153] mmcblk0: error -84 transferring data, sector 1, nr 31, cmd response 0x900, card status 0x0
[ 295.949645] end_request: I/O error, dev mmcblk0, sector 1
[ 295.954784] mmcblk0: error -84 transferring data, sector 2, nr 30, cmd response 0x900, card status 0x0
[ 295.967248] end_request: I/O error, dev mmcblk0, sector 2
[ 295.972221] Buffer I/O error on device mmcblk0, logical block 0
[ 295.975110] mmcblk0: error -84 transferring data, sector 8, nr 24, cmd response 0x900, card status 0x0
[ 295.984631] end_request: I/O error, dev mmcblk0, sector 8
[ 295.989962] mmcblk0: error -84 transferring data, sector 9, nr 23, cmd response 0x900, card status 0x0
[ 296.002122] end_request: I/O error, dev mmcblk0, sector 9
[ 296.004632] mmcblk0: error -84 transferring data, sector 10, nr 22, cmd response 0x900, card status 0x0
[ 296.013374] end_request: I/O error, dev mmcblk0, sector 10
[ 296.020513] mmcblk0: error -84 transferring data, sector 11, nr 21, cmd response 0x900, card status 0x0
[ 296.029621] end_request: I/O error, dev mmcblk0, sector 11
[ 296.034959] mmcblk0: error -84 transferring data, sector 13, nr 19, cmd response 0x900, card status 0x0
[ 296.045246] end_request: I/O error, dev mmcblk0, sector 13
[ 296.049056] mmcblk0: error -84 transferring data, sector 14, nr 18, cmd response 0x900, card status 0x0
[ 296.060881] end_request: I/O error, dev mmcblk0, sector 14
[ 296.063900] mmcblk0: error -84 transferring data, sector 15, nr 17, cmd response 0x900, card status 0x0
[ 296.076504] end_request: I/O error, dev mmcblk0, sector 15
[ 296.077780] Buffer I/O error on device mmcblk0, logical block 1
[ 296.085257] mmcblk0: error -84 transferring data, sector 17, nr 15, cmd response 0x900, card status 0x0
[ 296.096030] end_request: I/O error, dev mmcblk0, sector 17
[ 296.102900] Buffer I/O error on device mmcblk0, logical block 2
[ 296.110717] mmcblk0: error -84 transferring data, sector 0, nr 8, cmd response 0x900, card status 0x0
[ 296.113583] mmcblk0: retrying using single block read
[ 296.119562] mmcblk0: timed out sending r/w cmd command, card status 0x400b00
[ 296.125833] mmcblk0: command error, retrying timeout
[ 296.132753] mmcblk0: error -84 transferring data, sector 1, nr 7, cmd response 0x900, card status 0x0
[ 296.142064] end_request: I/O error, dev mmcblk0, sector 1
[ 296.146059] mmcblk0: error -84 transferring data, sector 2, nr 6, cmd response 0x900, card status 0x0
[ 296.154624] end_request: I/O error, dev mmcblk0, sector 2
[ 296.163335] mmcblk0: error -84 transferring data, sector 3, nr 5, cmd response 0x900, card status 0x0
[ 296.170251] end_request: I/O error, dev mmcblk0, sector 3
[ 296.176564] mmcblk0: error -84 transferring data, sector 6, nr 2, cmd response 0x900, card status 0x0
[ 296.185876] end_request: I/O error, dev mmcblk0, sector 6
[ 296.189699] Buffer I/O error on device mmcblk0, logical block 0
