Mathieu, John,
While looking into a CONFIG_CONSOLE_MUX-related issue, I noticed the following:
include/configs/u8500_href.h:136: "stdin=serial,usbtty\0" include/configs/u8500_href.h:135: "stdout=serial,usbtty\0" include/configs/snowball.h:180: "stdout=serial,usbtty\0"
Those all include multiple devices in the stdin/stdout definitions. However, those config files don't set CONFIG_CONSOLE_MUX. I assume this causes usbtty to be ignored, and only serial used?
Or perhaps U-Boot even fails to parse the variable at all, since CONFIG_SYS_CONSOLE_IS_IN_ENV isn't set on those boards? Actually, there are a few more boards with that problem:
include/configs/km/keymile-common.h:258: "stdout=serial\0" \ include/configs/MVBC_P.h:146: "stdout=serial\0" \ include/configs/MVBLM7.h:460: "stdout=serial\0" \ include/configs/MVSMR.h:129: "stdout=serial\0" \ include/configs/sandbox.h:91: "stdout=serial\0" \ include/configs/snowball.h:180: "stdout=serial,usbtty\0" \ include/configs/u8500_href.h:135: "stdout=serial,usbtty\0" \