bcm4708-smartrg-sr400ac boot failures in next/arm-soc

[linux@arm.linux.org.uk (Russell King - ARM Linux)]

On Fri, Jan 08, 2016 at 04:58:05PM -0800, Tyler Baker wrote:
> On 8 January 2016 at 16:21, Tyler Baker <tyler.baker@linaro.org> wrote:
> > I agree, and in my last reply I stated I did this. To be very
> > specific, I used "initrd=0x4000000,10M" which still did not work. Give
> > me a moment to reconfigure the scripts and I'll post and updated boot
> > log.
> 
> Here is the boot log when using "initrd=0x4000000,10M" [1]. Obviously,
> it does resolve the 'RAMDISK: EOF while reading compressed data'
> error, but still fails to mount.

Okay, thanks.  Things are better - there's another change in there.
We've gone from:

[    0.156295] Trying to unpack rootfs image as initramfs...
[    0.990981] rootfs image is not initramfs (read error); looks like an initrd

note the "read error" because we hit EOF while trying to read the
initramfs, which now has become:

[    0.156226] Trying to unpack rootfs image as initramfs...
[    0.993838] rootfs image is not initramfs (junk in compressed archive); looks like an initrd

I suspect the kernel has always complained about this, the difference
is that with BLK_DEV_RAM enabled, we will clean the initial rootfs,
which will return it to a pristine state after failed initramfs unpack.

Either way, turning off BLK_DEV_RAM doesn't _actually_ fix the problem -
it merely masks that the initramfs failed to properly unpack.

This is because unpack_to_rootfs() wants to consume all the data in the
passed image, so if you say it's 10MB in size, it will want 10MB of data.
So, I think the only proper solution is to set
"initrd=0x4000000,<actual-size>" and not "something that's larger"
which will prevent unpack_to_rootfs() reporting an error.

To prove this, if you look at a successful boot log from a kernel without
BLK_DEV_RAM enabled, I suspect you'll see:

Unpacking initramfs...
Initramfs unpacking failed: junk in compressed archive

in your log, which is just another symptom of the incorrect size being
passed.

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