Hello, I'm facing on my custom board issue with slow eMC write speed. When checked debug information I see that bus width is only 4 bit (while HW connection using 8 bit and in dts I've setup also 8): cat /sys/kernel/debug/mmc0/ios clock: 52000000 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: 1 (mmc high-speed) signal voltage: 0 (3.30 V) driver type: 0 (driver type B) and in bootlog I see: [ 4.001992] mmc0: switch to bus width 8 failed eMMC is sandisk (8G). Using mainline 4.12 kernel. IS there any way how to debug this issue or someone experiencing similar? Thanks. BR, marek
