PW4 Touchscreen software driver/hardware Issue with PW4

[CaesarW]

Hey everyone!

Recently I purchased a Kindle PW4 from a local shop and was really joyful to see the new kindle right out of the box. As a routine after my jailbreak, I tested typing from the kterm keyboard, and soon discovered the key 'P' and '[' were quite often mistyped. For example, when typing 'unzip abc.zip', if you don't pay special attention to your typing, it's very likely to be 'unzi[ abc.zi['.

I dived further into the issue and launched xtestlab126 in my terminal, and I discovered that on the right side of the screen, when I draw a line down the screen, the track on the screen would be a bit righter compared to my finger's physical track.The issue occurs especially near the place where the key 'P ; . [ ↑ ↓ ←' are located, the track drifted about 2mm.

So that explained why the keys listed are so easily mistyped. Meaning that if you touch on the righter part of the key 'P' on the keyboard, the drift will bring you to '[' on the keyboard. I've contacted Amazon to have my Kindle replaced and they accepted. After getting another *new* Kindle, I jailbroke it, and did the same test. The issue remains.

Now I'm posting this on the forum to ask if you guys who had a PW4 have the same issue? Or anyone help to test out if your PW4 has the same issue?Just can't be sure if this is a display manufacturing issue (hardware) or a touchscreen driver issue (software).

My hardware & software info:
Device: Kindle Paperwhite 4 with serial starting with G000.
Firmware: 5.10.1.2 jailbroken

I'll post the video reproduction of the issue later on the forum.

Thanks everyone for help!

[knc1]

Perhaps someone with time on their hands can look through the factory-use-only image and see if there is a ts calibration routine in it.
There has been in the past (hmm... might have been the IR TS only devices).

[CaesarW]

Originally Posted by knc1

Perhaps someone with time on their hands can look through the factory-use-only image and see if there is a ts calibration routine in it.
There has been in the past (hmm... might have been the IR TS only devices).

What kind of recalibration is that? Can it be done manually or done by upgrading to the latest firmware?

Or it's a issue caused by factory firmware image?

Thanks for the hint anyway.

[knc1]

Most (all?) touchscreen devices have to have their sensing alignment adjusted to match the display device.


So I expect that the people who put these things together would have such software.
And the one place I can think of to look for it would be on the factory-only firmware we are using to jb the devices.
That is: somewhere easy for the assembly people to access.

[CaesarW]

Originally Posted by knc1

Most (all?) touchscreen devices have to have their sensing alignment adjusted to match the display device.


So I expect that the people who put these things together would have such software.
And the one place I can think of to look for it would be on the factory-only firmware we are using to jb the devices.
That is: somewhere easy for the assembly people to access.

But the firmware I used for the jailbreak is a factory firmware.
I'll try upgrading to the latest firmware.

[PromethiumL]

Truth to be told, Caesar, those key buttons are much wider than the touch screen offset(2 mm), right? So how could you just mistype "p" to "["...which means you are not yet familiar with the new layout compared to the old one.

I didn't have such problem when testing your new device, I think.

[knc1]

Originally Posted by CaesarW

But the firmware I used for the jailbreak is a factory firmware.
I'll try upgrading to the latest firmware.

Correct.
And you know that you have to install a customer-use firmware before you can expect the features advertised to the customer to work (or work correctly).


Since you still have the Q.A. firmware install, dig through the diagnostics, see if you can find the ts test/calibrate routine(s).

Late Edit:
You should also be able to find the results of each of the factory tests as "erased files" on the user visible USB storage.
Use any DOS/WINDOZE FAT-32 un-erase program to find them.
There should be several from where your touchscreen was tested.

[CaesarW]

Originally Posted by knc1

Correct.
And you know that you have to install a customer-use firmware before you can expect the features advertised to the customer to work (or work correctly).


Since you still have the Q.A. firmware install, dig through the diagnostics, see if you can find the ts test/calibrate routine(s).

Late Edit:
You should also be able to find the results of each of the factory tests as "erased files" on the user visible USB storage.
Use any DOS/WINDOZE FAT-32 un-erase program to find them.
There should be several from where your touchscreen was tested.

I've upgraded to latest 5.10.2, the issue persists.
Haven't tried to recover files yet.
I'm wondering if this is a hardware issue. Given it's already been replaced by Amazon, this could hardly be.

[Krzywka]

Software development tends to be like that. It is extremely difficult to make sure there are no bugs. I remember working on my own medical device software - iec 62304 was really hard to meet. But all in all, through hard work and multitudes of testings I was able to eliminate all issues. Give them time and they'll make their work better as well, if they are persistent enough of course.

[CaesarW]

Originally Posted by Krzywka

Software development tends to be like that. It is extremely difficult to make sure there are no bugs. I remember working on my own medical device software - iec 62304 was really hard to meet. But all in all, through hard work and multitudes of testings I was able to eliminate all issues. Give them time and they'll make their work better as well, if they are persistent enough of course.

Yeah maybe I should contact lab126 or kindle feedback in the first place. :-)

[knc1]

Originally Posted by CaesarW

I've upgraded to latest 5.10.2, the issue persists.
Haven't tried to recover files yet.
I'm wondering if this is a hardware issue. Given it's already been replaced by Amazon, this could hardly be.

No, just the opposite.
All of Amazon and their refurbishment contractors use the same test and quality assurance software.
Something that is missed (or adjusted improperly) by that software for one will do the same for all, regardless of the number of times run.

Originally Posted by CaesarW

Yeah maybe I should contact lab126 or kindle feedback in the first place. :-)

Probably a good idea.
Too bad they don't give bug killer awards.

- - - - -

OK, deep breath, see if I can get the mind into system designer mode ...

Both the KOA2 and the PW4 have the "Androidized" system.
Where all other (firmware) series 5.x devices have been dual boot, these are better described as "dual mode".
They do not have a separate, storage backed, "Diags" system.
And, the KOA2 came first.

The initial, ram resident, system of the prior devices was often called the "Recovery System" by Amazon/Lab126.
What had been the functions of the storage backed "Diags" system has been moved into the initial fs "Recovery System".

Anyone who thinks the 512M memory size was a gift to the customer, please raise your hands.
Everyone with their hand raised, please stand in the hall and keep a look-out for

No, the 512M memory size is so the initial ram resident system can be large enough to run the "Diags" functions (even so, probably trimmed down a lot).

The TS registration (i.e: alignment with display) needed different parameters for the KOA2 (different screen dimensions).

When the PW4 was engineered, they forgot to put the parameters for the smaller dimension screen back into the calibration/registration diagnostic.
(People do not mess with the code, once working, in the initramFS system.)

End result:
The touchscreen reports a different than actual finger position at the right boarder of the display.
(With the same at the bottom of the display, which is rarely used. We have already had a few reports of the reading position display in the lowest left corner not working properly (can not select location display type) ).

Report to Amazon is:
"The touchscreen calibration routine for the PW4 is, incorrectly, using the KOA2 calibration parameters."
With the result: <describe here what you have found>

That should be worth a $25 bug killer award.