Sdcard debug

BAD vs GOOD card in debian

1. No card inserted - coldboot

   root@debian:~# cat /proc/interrupts | grep mmc
     16:         13         13         13         13   IO-APIC-fasteoi   mmc0
   

   root@debian:~# cat /sys/kernel/debug/mmc0/ios
   clock:          0 Hz
   vdd:            0 (invalid)
   bus mode:       1 (open drain)
   chip select:    0 (don't care)
   power mode:     0 (off)
   bus width:      0 (1 bits)
   timing spec:    0 (legacy)
   signal voltage: 0 (3.30 V)
   

   root@debian:~# cat /sys/kernel/debug/mmc0/clock
   0
   

2. BAD card inserted - coldboot

   root@debian:~# cat /proc/interrupts | grep mmc
     16:         13         13         13         13   IO-APIC-fasteoi   mmc0
   

   after card removal:

   root@debian:~# cat /proc/interrupts | grep mmc
     16:         13         14         13         13   IO-APIC-fasteoi   mmc0
   

   root@debian:~# cat /sys/kernel/debug/mmc0/ios
   clock:          0 Hz
   vdd:            0 (invalid)
   bus mode:       1 (open drain)
   chip select:    0 (don't care)
   power mode:     0 (off)
   bus width:      0 (1 bits)
   timing spec:    0 (legacy)
   signal voltage: 0 (3.30 V)
   

   root@debian:~# cat /sys/kernel/debug/mmc0/clock
   0
   

3. BAD card inserted - coldboot

   root@debian:~# cat /proc/interrupts | grep mmc
     16:        187        197        197        204   IO-APIC-fasteoi   mmc0
   

   root@debian:~# cat /sys/kernel/debug/mmc0/ios
   clock:          50000000 Hz
   actual clock:   50000000 Hz
   vdd:            21 (3.3 ~ 3.4 V)
   bus mode:       2 (push-pull)
   chip select:    0 (don't care)
   power mode:     2 (on)
   bus width:      2 (4 bits)
   timing spec:    2 (sd high-speed)
   signal voltage: 0 (3.30 V)
   

   cat /sys/kernel/debug/mmc0/clock
   50000000