(null): can't init uart3, no clocks available

[Paul Larson]

root@localhost:~# uname -a
Linux localhost.localdomain 2.6.35-1008-linaro-omap #15-Ubuntu Fri Oct 22 11:56:29 UTC 2010 armv7l GNU/Linux

When booting, I see the following warning. On most boots, it seems to be ok, and doesn't cause any problem that I've been able to notice. However, in the course of automating the process of booting new images, I'm trying to boot from a new rootfs on the card other than the default one, so I am controlling this over serial through uboot. here's what I've noticed:
1. when I keep the bootargs exactly as they are in boot.scr, it seems to work. It sometimes stops producing output at the same place that #2 describes, but then I eventually get a prompt on the serial console.

2. when I change the bootargs to have root=/dev/mmcblk0p2 instead of the uuid, it always stops at this point:
[ 0.763519] OMAP VENC rev 2
[ 0.982330] Freeing initrd memory: 4656K
[ 1.091766] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[ 1.178131] serial8250.0: ttyS0 at MMIO 0x4806a000 (irq = 72) is a ST16654
[ 1.346954] serial8250.1: ttyS1 at MMIO 0x4806c000 (irq = 73) is a ST16654
---stops here, the next lines would have been:
[ 6.055664] console [ttyS2] enabled, bootconsole disabled
[ 6.055664] console [ttyS2] enabled, bootconsole disabled
[ 6.073791] brd: module loaded
[ 6.080444] loop: module loaded

After that, I get NO further output, and never get control of the serial console.

Here is the log of the warning I get from the kernel in all cases, even booting the normal image with no changes whatsoever:
[ 1.091766] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[ 1.178131] serial8250.0: ttyS0 at MMIO 0x4806a000 (irq = 72) is a ST16654
[ 1.346954] serial8250.1: ttyS1 at MMIO 0x4806c000 (irq = 73) is a ST16654

[ 0.000000] ------------[ cut here ]------------
[ 0.000000] WARNING: at /build/buildd/linux-linaro-2.6.35/arch/arm/mach-omap2/serial.c:779 omap_serial_init_port+0x88/0x218()
[ 0.000000] (null): can't init uart3, no clocks available
[ 0.000000] Modules linked in:
[ 0.000000] [<c0055be4>] (unwind_backtrace+0x0/0x100) from [<c050e8f8>] (dump_stack+0x18/0x1c)
[ 0.000000] [<c050e8f8>] (dump_stack+0x18/0x1c) from [<c00807a8>] (warn_slowpath_common+0x5c/0x6c)
[ 0.000000] [<c00807a8>] (warn_slowpath_common+0x5c/0x6c) from [<c008085c>] (warn_slowpath_fmt+0x38/0x40)
[ 0.000000] [<c008085c>] (warn_slowpath_fmt+0x38/0x40) from [<c00108d4>] (omap_serial_init_port+0x88/0x218)
[ 0.000000] [<c00108d4>] (omap_serial_init_port+0x88/0x218) from [<c0010a94>] (omap_serial_init+0x30/0x3c)
[ 0.000000] [<c0010a94>] (omap_serial_init+0x30/0x3c) from [<c00126f0>] (omap3_beagle_init+0x6c/0xfc)
[ 0.000000] [<c00126f0>] (omap3_beagle_init+0x6c/0xfc) from [<c000c650>] (customize_machine+0x24/0x2c)
[ 0.000000] [<c000c650>] (customize_machine+0x24/0x2c) from [<c00423c4>] (do_one_initcall+0x3c/0x1dc)
[ 0.000000] [<c00423c4>] (do_one_initcall+0x3c/0x1dc) from [<c00085b4>] (do_basic_setup+0x64/0x74)
[ 0.000000] [<c00085b4>] (do_basic_setup+0x64/0x74) from [<c0008654>] (kernel_init+0x90/0x120)
[ 0.000000] [<c0008654>] (kernel_init+0x90/0x120) from [<c004f204>] (kernel_thread_exit+0x0/0x8)
[ 0.000000] ---[ end trace da227214a82491b7 ]---