MTK mt8173-evb: mainline unstable, and big-endian boot failures

On Thu, 2016-01-28 at 13:41 +0800, Koan-Sin Tan wrote:

Hi Kevin, 

On Thu, Jan 28, 2016 at 9:16 AM, Kevin Hilman [off-list ref]
wrote:
        Kevin Hilman [off-list ref] writes:
        
        [...]
        
        > It seems to be pretty stable up through v4.4 but
        > unreliable/unpredictable in v4.5-rc1 and lots of places in
        between.
        > It's hard to bisect because it doesn't reliably fail, but
        when it does
        > fail to finish booting, it's typically after it reaches a
        shell, and
        > trying to run various simple shell commands fails to
        complete, like
        > this example from next-20160125[2].
        >
        > To me this suggests possibly an issue with the idle driver
        where
        > characters might be getting lost on the serial console,
        which causes
        > the automated boot scripts to fail because the shell is
        still waiting
        > for the command to be finished.
        
        FWIW, I think I confirmed my suspicion that it's an idle
        driver issue
        because adding 'nohlt' on the cmdline, which forces
        cpuidle_poll mode
        (essentially disabling cpuidle) makes mainline boot quite
        reliably on my
        mt8173-evb board now.


   Thanks for the information. I'll try to reproduce it. The problem
is that I have been using 4.5-rc1 based kernel for several days, but
didn't run into such problem. Can tell me which version of firmware
you are using? 

Hi Kevin,

I use firmware [0] to run kernel v4.5-rc1 on my MT8173-evb, both branch
v20150716 (psci-0.2 atf) and v20150902 (psci-1.0 atf) can't reproduce
this problem.

[0]: https://github.com/ibanezchen/evb-utils

Eddie

  
   And, YES, I can reproduce the CONFIG_CPU_BIG_ENDIAN=y problem. The
'nohlt' command line option didn't stop the problem. We'll investigate
it.


-- 
// freedom