[meta-xilinx] : Can't boot from eMMC if bootargs maxcpu=1

[Nathan Rossi]

On 10 November 2017 at 02:20, Schmitt, Richard
<Richard.Schmitt at commscope.com> wrote:
> Using a 4.9 kernel (2017.1 SDK), trying to boot a kernel using an eMMC based
> rootfs will result in a crash
>
>
>
> The message preceeding the crash is:
>
>
>
> [    3.285566] VFS: Cannot open root device "mmcblk0p9" or
> unknown-block(0,0): error -6
> [    3.293338] Please append a correct "root=" boot option; here are the
> available partitions:
>
>
>
> Our kernel boot args can be seen in the boot log but for easy reference are:
>
>
>
>  root=/dev/mmcblk0p9 earlycon clk_ignore_unused cpuidle.off=1 DEBUG_MODE=y
> siq_board_type=RP maxcpus=1
>
>
>
> Note that we do specify root=/dev/mmcblk0p9.  If I simply remove maxcpus=1
> from the kernel boot args, the system will boot up fine.
>
>
>
> Seems like there might be a race in bringing up the eMMC partitions prior to
> mounting the rootfs but I don’t want to hypothesis any further.
>
>
>
> Any ideas?

Likely just a race between SD card not coming up fast enough before
the kernel tries to mount the rootfs.

Try adding "rootwait" to your boot args and see if the SD card appears
and mounts.

Regards,
Nathan