AnsweredAssumed Answered

Enabling boot console in Yocto

Question asked by Andrew Ellis on Nov 7, 2019
Latest reply on Nov 12, 2019 by Andrew Ellis

Hello

 

I am working on a project using an iMX6 and Yocto with kernel version 4.1.15. I would like to get a verbose output from the kernel sent to the serial console during the boot process. I have passed earlyprintk as a parameter to the kernel from uboot, and when the system boot I get the following output in the console:

 

Starting kernel ...

Uncompressing Linux... done, booting the kernel.
[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 4.1.15-yocto-standard (oe-user@oe-host) (gcc version 7.3.0 (GCC) ) #5 SMP PREEMPT Wed Nov 6 18:31:45 CE
T 2019
[    0.000000] CPU: ARMv7 Processor [412fc09a] revision 10 (ARMv7), cr=10c53c7d
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[    0.000000] Machine model: MSC Q7 i.MX6Q (143)
[    0.000000] bootconsole [earlycon0] enabled
[    0.000000] Memory policy: Data cache writealloc
[    0.000000] PERCPU: Embedded 12 pages/cpu @ee7a0000 s17100 r8192 d23860 u49152
[    0.000000] Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 520720
[    0.000000] Kernel command line:  coherent_pool=16M earlyprintk earlycon=imx21-uart,0x21e8000,115200n8 ttymxc1,115200 consoleblan
k=0 mtdparts=m25p16:0x0000020000@0x0000000000(init),0x0000020000@0x0000020000(uboot_data),0x0000080000@0x0000040000(uboot),0x0000140
000@0x00000c0000(boot_logo) root=/dev/mmcblk0p1 rw,rootwait ip=:::::eth0:off fec.macaddr=0x00,0x30,0xD6,0x16,0x48,0x85    board_name
=msc-q7-imx6plus board_id=1004305806 board_variant=143-012 boot_count=1211    uboot_version=2014.04+g3a5fc25
[    0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)
[    0.000000] Dentry cache hash table entries: 262144 (order: 8, 1048576 bytes)
[    0.000000] Inode-cache hash table entries: 131072 (order: 7, 524288 bytes)
[    0.000000] Memory: 1739116K/2097152K available (8147K kernel code, 369K rwdata, 2644K rodata, 316K init, 498K bss, 358036K reser
ved, 0K cma-reserved, 270336K highmem)
[    0.000000] Virtual kernel memory layout:
[    0.000000]     vector  : 0xffff0000 - 0xffff1000   (   4 kB)
[    0.000000]     fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
[    0.000000]     vmalloc : 0xf0000000 - 0xff000000   ( 240 MB)
[    0.000000]     lowmem  : 0x80000000 - 0xef800000   (1784 MB)
[    0.000000]     pkmap   : 0x7fe00000 - 0x80000000   (   2 MB)
[    0.000000]     modules : 0x7f000000 - 0x7fe00000   (  14 MB)
[    0.000000]       .text : 0x80008000 - 0x80a9206c   (10793 kB)
[    0.000000]       .init : 0x80a93000 - 0x80ae2000   ( 316 kB)
[    0.000000]       .data : 0x80ae2000 - 0x80b3e440   ( 370 kB)
[    0.000000]        .bss : 0x80b3e440 - 0x80bbaf10   ( 499 kB)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[    0.000000] Preemptible hierarchical RCU implementation.
[    0.000000] NR_IRQS:16 nr_irqs:16 16
[    0.000000] L2C-310 erratum 769419 enabled
[    0.000000] L2C-310 enabling early BRESP for Cortex-A9
[    0.000000] L2C-310 full line of zeros enabled for Cortex-A9
[    0.000000] L2C-310 ID prefetch enabled, offset 16 lines
[    0.000000] L2C-310 dynamic clock gating enabled, standby mode enabled
[    0.000000] L2C-310 cache controller enabled, 16 ways, 1024 kB
[    0.000000] L2C-310: CACHE_ID 0x410000c7, AUX_CTRL 0x76070001
[    0.000000] ccm: ldb_di_sel already changed from reset value
[    0.000000] mxc_clocksource_init 3000000
[    0.000000] Switching to timer-based delay loop, resolution 333ns
[    0.000009] sched_clock: 32 bits at 3000kHz, resolution 333ns, wraps every 715827882841ns
[    0.008300] clocksource mxc_timer1: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 637086815595 ns
[    0.018922] Console: colour dummy device 80x30
[    0.023479] console [tty0] enabled
[    0.026986] bootconsole [earlycon0] disabled

After the line stating the bootconsole is disabled, I see no further output until the login prompt.I have spent some time searching for an answer, but so far I've not found anything that helps.

 

How do I enable the boot console so I get a verbose output from the kernel during booting?

 

Thanks in advance

 

Andrew

 

imx6 quadplus

yocto warrior

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