mmc extcsd write does not take effect

[xueyf]

Hello,NXP support

     I encountered a problem when using the IMX8MP platform。I want the Host to send CMD6+PoN (power off notification) to eMMC。So I used this command

     mmc extcsd write 34 0x04 /dev/mmcblk2

    But when I use mmc extcsd read /dev/mmcblk2 to read whether extcsd[34] has been modified, the result is that extcsd[34] is not the value I wrote, and I cannot modify the value of extcsd[34].
    Do you have any suggestions to help me solve this problem?
    I want to send CMD6+PoN to eMMC, Use CMD6 to Write 0x04 in Ext_CSD[34] for Sleep-Notification before turn off VCC

[xueyf]

Attachment information

[JosephAtNXP]

Hi,

Thank you for your interest in NXP Semiconductor products,

mmc-utils doesn't have send cmds as their features in this documentation found here,

Regards