[LEDE-DEV] kernel 4.9 migration for next release

[Hauke Mehrtens]

On 10/04/2017 03:58 PM, p.wassi at gmx.at wrote:
> Hi Hauke, Hi Rafal,
> 
>> The following targets are on kernel 4.4 and need a upgrade to kernel 4.9
>> to be included:
>> * brcm47xx
>> 	4.9 patches available
>> 	Some devices have problems with "big" kernel images
>> 	@Rafał: did you explain this in some mail in detail were you saw
>> 	these problems, I would like to investigate this.
> 
> The WL500gPv2 is working fine (see [1]).
> The WRT54GL is one of the devices, which always had problems with 4.9
> (and also 4.4 in trunk with KALLSYMS enabled)
> 
> @Hauke: I just did some kind of 'investigation' and probably found a solution
> or at least a workaround for me. But as I'm not an expert in CFE and booting,
> I have no idea whether (and why) my findings really are the issue's origins.
> And if this can be fixed in the loader or must be fixed in the CFE.
> Please check out (and maybe also try yourself) what I've documented at [2].
> 
> My WRT54GLs are now booting kernel 4.9 :-) 
> (Being happy to (still) have 'current trunk' on the good old WRTs)
> 
> Regards,
> P. Wassi
> 
> [1]:
> https://pwassi.privatedns.org/lede/brcm47xx/wl500gpv2/
> 
> [2]:
> https://pwassi.privatedns.org/lede/brcm47xx/wrt54gl/
> 

Thank you for your analysis.

Do you have JTAG connected to your devices?

Do you know how the boot process works in detail, so when memory gets
moved to which position? Your findings support my assumption that some
memory region is overflowing. We still have the loader in between on
some devices it could be possible to change the way we unpack the
kernel, but I am not so familiar with the boot process.

Hauke