[U-Boot] fit image: boot gzipped ramdisk does not work anymore

[Simon Goldschmidt]

Hi Heiko,

On Fri, Aug 2, 2019 at 6:08 AM Heiko Schocher <hs at denx.de> wrote:
>
> Hello Julius,
>
> Am 01.08.2019 um 20:24 schrieb Julius Werner:
> >> First, we have a problem as we need to support what's out in the world.
> >
> > How about I write a patch to change the decompression call in
> > fit_image_load() to fall back to a memcpy() if the decompression fails
> > (and print a big warning that the FIT image is wrong and should be
> > updated)? That should keep those old installations working.
>
> Hmm.. what happens if decompression does not fail ?
> (I wonder, why I get this Error, but I go into vacation, so I have
>   no chance to dig deeper into it soon ...)
>
> And why should we decompress, if we "know" we do not have to (in ramdisk
> case)? This cost only boottime ...

It's correct we don't need to decompress since the kernel can decompress the
ramdisk. However, the FIT image is wrong (given our updated definition of the
"compressed" field) and it's only decompressed on "legacy" images.

>
> For the fast track, I prefer to ignore the compression property in ramdisk
> node ... (may configurable through a Kconfig option with default to ignore)

I'm not too fond of adding such extra cases, but you're right that
decompressing a ramdisk is probably never needed...

Regards,
Simon

>
> >> Second, what is intended with what's out in the world?  Indeed before we
> >> didn't do anything with the compressed data.  But now what, we're saying
> >> it's compressed, but not providing enough details to U-Boot to
> >> uncompress it?
> >
> > Hmm... I'm not sure why it wouldn't just decompress correctly,
> > actually. Is there anything special with how gzipped data is formatted
> > for the kernel decompressor? Or is there any limitation in the U-Boot
> > gzip implementation?
> >
>
> I do not know.
>
> bye,
> Heiko
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