← Back to team overview

kernel-packages team mailing list archive

[Bug 1248233] Re: [saucy][armhf] No early printk because there's no defined device tree binding for earlyprintk UART


I can verify that the patch fixes the bug above, with this patch I am
able to see messages at boot...

[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Initializing cgroup subsys cpuset
[    0.000000] Initializing cgroup subsys cpu
[    0.000000] Initializing cgroup subsys cpuacct
[    0.000000] Linux version 3.11.0-15-generic-lpae (buildd@kishi02) (gcc version 4.7.3 (Ubuntu/Linaro 4.7.3-7ubuntu3) ) #22-Ubuntu SMP Tue Dec 3 01:16:52 UTC 2013 (Ubuntu 3.11.0-15.22-generic-lpae 3.11.10)
[    0.000000] CPU: ARMv7 Processor [413fc0f2] revision 2 (ARMv7), cr=30c7387d
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, PIPT instruction cache
[    0.000000] Machine: Dummy Virtual Machine, model: linux,dummy-virt
[    0.000000] cma: CMA: reserved 16 MiB at 36800000
[    0.000000] Memory policy: ECC disabled, Data cache writealloc
[    0.000000] psci: probing function IDs from device-tree
[    0.000000] PERCPU: Embedded 9 pages/cpu @c11f5000 s14400 r8192 d14272 u36864
[    0.000000] Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 260624

You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.

  [saucy][armhf] No early printk because there's no defined device tree
  binding for earlyprintk UART

Status in “linux” package in Ubuntu:

Bug description:
  SRU Justification:

  Impact: earlyprintk doesn't work in mach-virt (qemu guest target for
  kvm on arm) because at boot time, the clock necessary to make pl011
  serial port running is not added via device tree (and thus the serial
  console is not probed) - also see https://lists.gnu.org/archive/html

  Fix: apply the attached patches and recompile a kernel.

  Test case: try booting a patched (and an unpatched kernel) in kvm
  guest passing earlyprintk and NO console, and see if it emits any


  There is no earlyprintk via the PL011 because there's no defined
  device tree binding for earlyprintk UART to get the PL011 to work
  you'll need to tweak the kernel a bit. kernel doesn't ever add the
  clock to its list, and then it refuses to probe for the PL011. This is
  a temporary fix, ideally the call should be done in some generic
  location rather than in every machine's init function.) The
  alternative would be for the kernel to be fixed to follow its own
  device tree binding documentation and not require clocks/clock-names
  properties on the pl011 node.

To manage notifications about this bug go to: