4.13 (and probably all recent) kernels refuse to boot on one Nokia N950, work or another

[Pali Rohár]

On Thursday 26 October 2017 09:27:59 Pavel Machek wrote:
> Hi!
> 
> On Thu 2017-10-26 09:21:13, Pali Rohár wrote:
> > On Thursday 26 October 2017 09:08:15 Pavel Machek wrote:
> > > On Thu 2017-10-26 08:25:02, Filip Matijević wrote:
> > > > Last time I couldn't get output on serial I used CONFIG_DEBUG_LL,
> > > > CONFIG_DEBUG_OMAP3UART3, CONFIG_EARLY_PRINTK... and ignore_loglevel
> > > > earlyprintk kernel params to get output early enough - I guess you
> > > > already tried that.
> > > 
> > > I realized I'm not getting output from the decompessor (even on "S"
> > > machine), and enabled that.
> > 
> > That is because you have not enabled those EARLY PRINK or DEBUG LL.
> > Similar thing is needed for N900 and IIRC in some of my linux-n900
> > branches I have config for it. Plus it needs patching some arch/arm
> > source files to make it working.
> 
> Do you have a patch? That would be very useful.

Yes, in v4.9-n900 branch, see:
https://github.com/pali/linux-n900/commit/66b22ba4132ca90f7efc3f9e8ece8d4b9adddcdc

> Seems like debugging in uncompressor was broken some time ago:
> 
> config DEBUG_UNCOMPRESS
>         bool
> 		depends on ARCH_MULTIPLATFORM || PLAT_SAMSUNG ||         ARM_SINGLE_ARMV7M
> 	        default y if DEBUG_LL && !DEBUG_OMAP2PLUS_UART && 
> 		                     (!DEBUG_TEGRA_UART || !ZBOOT_ROM)
>         && \!DEBUG_BRCMSTB_UART
> 			     
> 
> > > But I'm _still_ not getting any output on decompressor... early
> > > printing works ok on "S" but not on "P".
> > 
> > I guess there can be either problem with memory mapping and RAM size or
> > with OMAP HS mode?
> 
> RAM size should be ok... how do I check for OMAP HS problems?

For problems with smc or any other it is needed to look into kernel log :-(

-- 
Pali Rohár
pali.rohar at gmail.com