Re: rock64 verbose boot hangs

On Wed, 29 Sep 2021 20:07:25 +0300
Andriy Gapon <[email protected]> wrote:

> On 23/09/2021 20:46, Andriy Gapon wrote:
> > On 20/09/2021 20:02, Emmanuel Vadot wrote:
> >>
> >>   Hi Andriy,
> >>
> >> On Sat, 18 Sep 2021 15:58:00 +0300
> >> Andriy Gapon <[email protected]> wrote:
> >>
> >>>
> >>> Normal boot works every time, but with boot_verbose="YES" it hanged on all
> >>> attempts so far.
> >>>
> >>> Last messages on the console:
> >>> cpulist0: <Open Firmware CPU Group> on ofwbus0
> >>> cpu0: <Open Firmware CPU> on cpulist0
> >>> cpu0: Nominal frequency 600Mhz
> >>> cpufreq_dt0: <Generic cpufreq driver> on cpu0
> >>> cpufreq_dt0: 408.000 Mhz (950000 uV)
> >>> cpufreq_dt0: 600.000 Mhz (950000 uV)
> >>> cpufreq_dt0: 816.000 Mhz (1000000 uV)
> >>> cpufreq_dt0: 1008.000 Mhz (1100000 uV)
> >>> cpufreq_dt0: 1200.000 Mhz (1225000 uV)
> >>> cpufreq_dt0: 1296.000 Mhz (1300000 uV)
> >>> cpu1: <Open Firmware CPU> on cpulist0
> >>> cpu1: Nominal frequency 600Mhz
> >>> cpufreq_dt1: <Generic cpufreq driver> on cpu1
> >>>
> >>> The kernel is totally unresponsive after that.
> >>
> >>   Can't reproduce here, I'm running 548a706608d with latest DTB and
> >> latest u-boot/atf
> >>
> >>> Any suggestions on how to debug this?
> >>
> >>   Not really sure how to start, that seems weird that the kernel will
> >> hang at the cpufreq attach but maybe try modifying the DTB to remove
> >> this node ?
> >>   Also did that happens with my recent commit on clock or was this the
> >> same before ?
> 
> An update relevant to the question above.
> Actually, after upgrading to a version that includes your clock changes the 
> problem went away!
> I don't know what to make out of this fact, but it looks like the problem was a 
> clock plus timing issue.

 I'm not that surprised. Before my clock changes netboot always failed
in a really weird way where AP couldn't be started and the serial
output was switching chars around (Like "cuolt'd rsart AP").
 So I'm glad that it fixed your problems because I had really no idea
how to debug that :P

> > Thank you and every one else who responded with information and suggestions.
> > 
> > Some extra details.
> > I've been having this problem since I've got this board 9 months ago.
> > It's been through several FreeBSD and U-Boot and stuff in the ESP partition 
> > upgrades.  And the problem was always present.
> > 
> > Now I've done more extensive testing with a couple of dozen reboots in a row and 
> > some additional debug prints (like, for example, DEBUG in subr_bus.c).
> > 
> > I actually see several variations of the problem.
> > Sometimes it's a hang, but sometimes it's a crash.
> > A hang can happen in different places and a crash can happen in different places 
> > too.
> > Some crashes happens during AP startup and the information I am getting is not 
> > very usable.
> > Some crashes happen during a driver probing when the bus code searches the hints 
> > memory space.  Those crashes look like a memory corruption happens there at random.
> > 
> > Given those variations plus some other differences that I have comparing to 
> > other Rock64 users (like needing special setup for eMMC and for the watchdog), I 
> > am inclined to think that the board I have has something special either in the 
> > hardware (like a different configuration via some fuses) or in the BootROM.
> > Even though the PCB has the standard markings.
> > 
> > And I would not be surprised about that (that it could be a customized 
> > production) as I got my Rock64-s via a special / unusual deal on Amazon. 
> > Iconikal and Recon Sentinal are keywords to search for, for those interested.
> > Some news articles from the time:
> > https://liliputing.com/2020/09/this-10-single-board-computer-is-faster-than-a-raspberry-pi-3.html 
> > 
> > https://www.tomshardware.com/news/raspberry-pi-sized-iconikal-rockchip-sbc-only-dollar8-on-amazon 
> > 
> > 
> > So, in the end, I still do not know what causes the verbose boot to hang / crash.
> > Maybe there is some (not fully working) watchdog that gets armed and disarmed by 
> > some hardware accesses and the verbose boot is too slow to complete in time.
> > 
> > Here is a small subset of panics and hangs that I saw:
> > https://people.freebsd.org/~avg/rock64-verbose-boot-panic.txt
> > 
> 
> 
> -- 
> Andriy Gapon
> 


-- 
Emmanuel Vadot <[email protected]> <[email protected]>