Author Topic: ICS on single speaker apad clone-y tablet  (Read 5294 times)

theintersect

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ICS on single speaker apad clone-y tablet
« on: December 14, 2011, 02:29:44 PM »
So... I started working on ICS for work, and we happen to also use Freescale processors, so I figured I might as well crack out the old Shenzhen tablet and see if I could get it booting.  The good news: I can, the bad news: I broke my touch screen in the process (specifically I tore the ribbon cable where it plugs in to the board :( );

Here is a video of what I have so far.  Note that it isn't much ;)

http://www.youtube.com/watch?v=NPOLsNAr218

There is a high pitched squeel when the screen turns on.  I believe that I have some frequency wrong in the board support, or the mode line is wrong somehow.  If someone could provide me with the following since I don't have a touch screen and adb doesn't seem to want to start on either cupcake *or* ICS for me for some reason...

The output of /proc/kmsg - I'm curious about a few lines and I *had* the output but unfortunately, my text editor crashed (grr gnome3) before I saved the output.

The output of logcat would also be nice.

Anyway, I plan to keep people posted.  As I mentioned in the other thread, this is using our internal GLES binaries, so I can't release it just yet.  And really, until I snag the working one from our office (I tend to work from home); I can't particularly test it very well.  Once I have it to a workable state, I intend on making more of the sources publicly available (they are actually on github already just in private repos.)

Destroyer

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Re: ICS on single speaker apad clone-y tablet
« Reply #1 on: December 18, 2011, 03:32:29 AM »
The high Frequency whine is either:

1. the back light drive transformer defective (you can test this with the old firmware, if it works then that is not the cause)

2. Seriously 'off' screen perimeters,  if this is the cause it is a very good Idea not to let the situation progress, since i have seen it cause destruction of the LCD driver chips.

theintersect

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Re: ICS on single speaker apad clone-y tablet
« Reply #2 on: December 23, 2011, 04:18:59 PM »
It's definitely the latter.  I know it's something in the kernel, I'm just not sure what... if you happen to have a pointer, I'm all ears :)

Destroyer

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Re: ICS on single speaker apad clone-y tablet
« Reply #3 on: December 23, 2011, 11:35:58 PM »
Normally the screen parameters are 'encoded' in the startup configuration command passed from the boot loader to the Kernel
'If' you still have a copy of your original image file from the device, a simple Hex editor can be used.

for an example to take a look here:

http://hardcoreforensics.com/wp/forum/index.php?topic=22.msg46#msg46

At the second screen capture, you can clearly see the video mode encoded into the 'bootargs' startup command, it gives the buffer address and the resolution+scan rate.

if you have a look at this link:
http://hardcoreforensics.com/wp/forum/index.php?topic=26.0

you will see the actual hex as it appears on the image

Just find this information on 'your' image

theintersect

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Re: ICS on single speaker apad clone-y tablet
« Reply #4 on: December 25, 2011, 11:58:58 PM »
That's what I thought, there has to be something kernel-side that is different (which is entirely possible, I'm using freescale's 2.6.35 kernel as a base instead of the 2.6.31 kernel that comes on the original sd card); I'm already passing the mxcdi1fb:800x600M-16@60, although I wasn't passing di1_primary though that shouldn't matter.

Aha, okay, I cracked out our old sources (2.6.31) and I see the babbage change for 800x600M-16@60, so I'll try throwing those into 2.6.35 and see if that helps at all.
« Last Edit: December 26, 2011, 01:45:32 AM by theintersect »

Destroyer

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Re: ICS on single speaker apad clone-y tablet
« Reply #5 on: December 27, 2011, 12:38:10 AM »
It is usually better to keep things exactly the same until the thing is up, then start to make changes.
Iv'e seen cases where I have made changes that 'did not matter' only to find out later that it would cost me several days and it 'did matter'.

I was recently running some timing tests with a logic analyzer, on power up of the particular board, all the I/O were randomly strobing during bootup, making the Logic analyzers trigger conditions difficult to setup, so in my code I set a unique combination of bits.

port=b00000001
port=port|b10000000

then looked for a high toggle on bit 7 plus 0x81 on the Logic analyzers triggers, and it worked fine
but then I got clever and cleaned up the code

port=b10000000
port=port|b00000001

and it stopped working........

the reason was that the  Logic analyzers triggers were looking for a high toggle on bit 7 then checking for 0x81, but because the timings for setting the port were delayed by 100ns, the logic analyzer was being woken for the high toggle on bit 7 (0x80) which is not 0x81 and then ignored the 0x01 which is also not a toggle on bit 7, so even though the overall result in the port was 0x81 the reversal of two lines of code made it fall apart.

HC

PS
The test was for the Arduino, I had seen some software timings for setting/unsetting ports on the internet and they did not look right.

Destroyer

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Re: ICS on single speaker apad clone-y tablet
« Reply #6 on: January 22, 2012, 01:40:59 AM »
Be more specific on your question.


theintersect

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Re: ICS on single speaker apad clone-y tablet
« Reply #7 on: March 03, 2012, 11:29:36 PM »
Mostly because we work with freescale processors where I work, so I have access to their internal copies of ICS/HC and was able to modify what we were working on to work for the tablet as well.  (Basically I took the mx51_babbage or whtever they call it and renamed it... but newer releases of theirs target only mx53 and mx6.  Which is fine, you can use the rootfs from one of the mx53 boards just fine on mx51 by swapping in a proper kernel and such)