[Kindle3] cat:can't open '/sys/devices/platform/charger/globals': No such file or dir

[Frenko]

Hello guys!

Quite some time ago I bricked my Kindle 3 EU (not US) wi-fi only.

Spoiler:

Here is the full backstory:
https://www.mobileread.com/forums/sho...d.php?t=154674 <- how I bricked it
https://www.mobileread.com/forums/sho...d.php?t=170547 <- my serial setup

Now that I'm trying to repair it, I got my serial connection going (kudos to knc1 without whom I would still be looking at a blank screen ) but in hyperterminal's console I get this error

cat: can't open '/sys/devices/platform/charger/globals': No such file or directory

that keeps looping over and over again (and I don't know how to send a break command)

If I press enter it returns

Welcome to Kindle!

kindle login:

immediately followed by the ever looping error

Spoiler:

as so

cat: can't open '/sys/devices/platform/charger/globals': No such file or directo
ry
cat: can't open '/sys/devices/platform/charger/globals': No such file or directo
ry



Welcome to Kindle!

kindle login: cat: can't open '/sys/devices/platform/charger/globals': No such f
ile or directory
cat: can't open '/sys/devices/platform/charger/globals': No such file or directo
ry

What to do?

Cheers,

f

[knc1]

Originally Posted by Frenko

If I press enter it returns

Welcome to Kindle!

kindle login:

immediately followed by the ever looping error

Just close your eyes and keep on typing whatever is expected for the login response.
It is a full duplex serial line, it is listening to your key strokes even while outputting other messages.

Then, once you log in, we just need to find and stop what is sending the error messages. Not to fix the overall problem, but just so the serial line can be used without a bunch of distracting chatter from something failing.

Hints:
Turn on the 'capture' feature of your terminal and save the capture file. It may be neccessary to use a text editor on the capture file to sort out the input/output from the error message chatter.

If your terminal has a provision to define 'keystroke macros' (strings sent in response to a specific key combination), it may be neccessary to use that for the various things to be sent to the kindle (like the login strings).

And/Or - check if your terminal has a 'hand off' feature (many do) it may be neccessary to use that to turn the serial line over to an 'expect' or 'chat' script.

Some terminal emulators have such a 'chat' feature included, left over from dealing with modems and dial-up connections. It may be neccessary to use that to get past the chatter.

Eventually we will get to the point where we can get a process list of what is running (using either 'ps aux' or 'top -bn1') -
It is one of those things which:
Is a script;
Is calling 'cat';
Does not have stderr redirected;
And not checking the error return from the 'cat' command.
(And from the content of the message, wants to know if the charger is connected and the state of the battery charge but is doing it Before the software charger controls are loaded. I.E: a start-up script without the proper dependences set.)

Notes:
Linux (any *nix) starts up with only an "operator's console line" (/dev/console) to communicate with the outside world. Everything else is add-ons by other programs.
Something (which shouldn't be by design) is still talking to /dev/console.

Linux (any *nix) is a single, stand-alone, program that only runs one other program when it is ready to run anything at all.

The usual default is a special program that starts, controls and stops multiple other programs but it does not have to be. A common debugging setting is to set either: 'init=/bin/sh' or 'rdinit=/bin/sh' on the kernel command line.

That leaves the system as just you, the kernel, and the command shell talking on /dev/console. No chance for anything else to start up (and fail) while locating the source of the original problem.

Changing the kernel command line arguments in an embedded system is done from the boot loader (here: u-boot) with commands to 'setenv', 'getenv', etc.

Translation: This is good progress, just a bit messy with all of the chatter going on.

O.P. first complains his machine will not talk to him. Now complains that it says too much. What will make him happy?

[geekmaster]

When I debricked my touch using the serial port, it would halt at the repair needed screen within 10 to 30 seconds after I logged in, which terminated my serial port session. I successfully "uploaded" and ran a few scripts to debug and repair it by copying the script contents to the clipboard and pasting it to my serial terminal immediately after logging in. And yes, you need to ignore a LOT of status messages interleaved with your desired output.

It took a few passes, after I pasted some "scripts" to snoop around and display output (which I later analyzed in my terminal scrollback buffer). Then finally, I pasted script contents into my serial login session that fixed the problem (a broken startup script).

Even if you have access for only 10 seconds per reboot, you CAN investigate and repair your kindle like I did.

[geekmaster]

Originally Posted by knc1

O.P. first complains his machine will not talk to him. Now complains that it says too much. What will make him happy?

He just needs to activate the kindle's voice recognition, and shout "Kindle, heal thyself!", while seated in a lotus position with his kindle cradled lovingly in his lap (although I hear that the results obtained by this method depend on the phase of the moon and the alignment of the planets).

[Frenko]

Thank you both!

In the last episode I managed (with some help) to connect the kindle to the pc... but my brain must have gotten disconnected in the process

What we were looking at was the output after a "normal boot"

I just had to keep holding the power switch a little longer (I got fooled by the blinking led) and this is the output after a "hard reset"

U-Boot 1.3.0-rc3-lab126 (Feb  5 2011 - 19:03:59)

CPU:   Freescale i.MX35 at 532 MHz
Board: MX35 Luigi [ POR]
WDOG_WCR = 0xff31
WDOG_WMCR = 0x0
Board Id: SP1B000000000000
S/N: B008XXXXXXXXXXXX
DRAM:  256 MB
Using default environment

In:    serial
Out:   serial
Err:   serial
No ethernet found.
i.MX35 CPU board version 2.0
Net:   No ethernet found.
Hit any key to stop autoboot:  0
## Booting image at 87f40400 ...
   Image Name:   Linux-2.6.26-rt-lab126
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    2166568 Bytes =  2.1 MB
   Load Address: 80008000
   Entry Point:  80008000
   Verifying Checksum ... OK
   Loading Kernel Image ... OK

Starting kernel ...

Uncompressing Linux.............................................................
............................................................. done, booting the
kernel.
boot: C def:bcut:batterycut=1:
2.6.26-rt-lab126 #5 Sat Feb 5 19:05:05 PST 2011 armv6l
INFO:Using default keypad setting. (not passing "kb_rev" to module)
INFO:Loaded module /lib/modules/mxc_keyb.ko  (22508 bytes)
Press [ENTER] for recovery menu...       0 /
INFO:Partition table verified for /dev/mmcblk0
INFO:Loaded module /lib/modules/eink_fb_hal.ko  (73284 bytes)
[...]

Now if I understand correctly I should hit enter to access the recovery menu then select 3 and then enter my fiona password (that should be obtainable with md5sum -s=S/N and cutting off 3 or 4 digits Wrong! Working on it.), etc.
Ok, one step at a time... back to studying and experimenting and let's hope my brain is connected this time around (finger crossed )

All jokes aside I'm really sorry to have wasted your time.

Originally Posted by knc1

O.P. first complains his machine will not talk to him. Now complains that it says too much. What will make him happy?

Nothing. That is called "being human" I guess?

Cheers,
f

EDIT:

Originally Posted by geekmaster

He just needs to activate the kindle's voice recognition, and shout "Kindle, heal thyself!", while seated in a lotus position with his kindle cradled lovingly in his lap (although I hear that the results obtained by this method depend on the phase of the moon and the alignment of the planets).

That sounds cool but... happy? I'm not sure
...and, might I add, the most unlikely part of what you've written is me sitting in a lotus position I'm so rigid sometimes I think I'm dead and I didn't noticed yet

[giorgio130]

A way for making the statement go away could be a
touch /sys/devices/platform/charger/globals
that would create the missing file. I don't know if it would work but it's worth a try

[Frenko]

Originally Posted by giorgio130

A way for making the statement go away could be a
touch /sys/devices/platform/charger/globals

Grazie Giorgio

But to be fair I was thinking of ignoring the error and go on with the unbricking attempt just for now.

Cheers,
f

[knc1]

Originally Posted by giorgio130

A way for making the statement go away could be a
touch /sys/devices/platform/charger/globals
that would create the missing file. I don't know if it would work but it's worth a try

The /sys file tree is dynamically created and maintained by the kernel.
You can't create directories there, and only very rarely, write to anything.