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Old 07-14-2011, 01:30 PM   #1
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!!! no more screen flashing !!!

OK... so this is not perfect, but surprisingly usable. I've disabled the page-refresh-flash and cranked up the contrast, and my K3 (v3.1) is usable- if a little bit ugly.

I created a script, /etc/init.d/local that says
echo 19 7 > /proc/eink_fb/update_display
echo 1 > /sys/devices/platform/eink_fb.0/override_upd_mode

and from /etc/rc5.d, ln -s ../init.d/local S97local to start it at boot, but you could just type the echos from a shell to see the effect... It is in no-way permanent.

The "19 7" above sets contrast to an undocumented (very dark) setting, necessary to overcome the eInk - which has an almost mechanical latency to it and is too light otherwise. I found a pretty good bit of documentation, indirectly, in /opt/eink/scripts/diags.

I don't think Amazon will enable this as an option because there is a little bit of ghosting and overall ugliness to the display, but for me it works quite well, and the ultra-contrast actually makes many of my books easier to see in low light.

I've asked around to see if someone can help me get the eInk firmware from the new Nook STR (with it's proprietary anti-flash tech) to see if I can apply it to Kindle.

whatcha think?

******************************************

UPDATE 8/4/11
Just a quick update before this thread fades into obscurity (or someone actually releases something : ) to save you the trouble of reading this whole boring development thread... Essentially we succeed to disable the screen flash, and solution is very usable.

If you read up to page three, you'll find a few different algorithms to change the way the eInk updates; there are essentially 3 update sequences with various effects. I hacked it, seaniko7 did the first proof of concept and made a video - http://www.youtube.com/watch?v=VN5fd3iBsMA

Various ideas were tried, in my opinion the current winning solution is mobad's script at
http://pastebin.com/pS83izMi

Enjoy, and thanks everyone for participating!
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Last edited by khmann; 08-08-2011 at 12:34 AM.
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Old 07-15-2011, 12:37 AM   #2
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common... 126 post-reads already, somebody comment! I'm excited.. this totally works... surprisingly well. I'm pretty sure that with a little bit of help, eink flashing could be a thing of the past on Kindle.

I should note that I'm using a B006 K3,
[root@kindle root]# cat /proc/eink_fb/commands_version
V0303 (C/S 0000EB65)
[root@kindle root]# cat /proc/eink_fb/waveform_version
V220_C049_60_WJ0F01_D (M24, S/N 1500, 85Hz)

"contrast level 7" seems to be a special 1 bit display mode, which interestingly, ignores /sys/devices/platform/eink_fb.0/override_upd_mode (which to get the following trick to work, should be left/put back at default... 0) Perhaps if a user-mode daemon was written to monitor page turns and fire the following "refinement":

echo 19 3 > /proc/eink_fb/update_display ; echo 18 0 > /proc/eink_fb/update_display ; echo 19 7 > /proc/eink_fb/update_display

firing this ^^^ after a page turn results in a 4bit grayscale refinement to the 1bit rendered page of contrast 7, it looks like there is still "1 bit" of ghosted afterimage but it looks good.

-----------------------------------------------------
notes:

_EINK_UPDATE_DISPLAY_WHICH=18
_FX_UPDATE_PART=0
_FX_UPDATE_FULL=1
_FX_UPDATE_FAST=2
_FX_UPDATE_SLOW=3 - full refresh with "flash"

_FX_BUFFER_LOAD=99
_FX_DISPLAY_PART=100
_FX_DISPLAY_FULL=101
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Old 07-15-2011, 05:25 AM   #3
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Very interesting, I'll experiment a bit with this is it possible that the "undocumented" very dark setting is harmful to the display?

edit: indeed this is fast, I don't really like it's disabling the antialiasing of the fonts.
How do I get back to standard values?

Last edited by giorgio130; 07-15-2011 at 02:40 PM.
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Old 07-15-2011, 07:09 PM   #4
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It's great, I was looking for it.
I enjoyed with similar option in Duokan firmware , I put in "Full Refresh" option as a value of pages before full page refresh (Flashing to Black), and I can clean (refresh) the screen any time by [Enter] key (Kindle shortcut key for screen refresh is: Alt+G).

Now this option is availible in Nook Touch and Kobo Touch but it limited by 6 pages only before full refresh.

Can you make an install and uninstall script for this idea ?

Last edited by meem; 07-15-2011 at 07:16 PM.
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Old 07-15-2011, 10:51 PM   #5
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"Contrast: Off" = default
echo 19 0 > /proc/eink_fb/update_display

I think for now, we don't need to mess with /sys/devices/platform/eink_fb.0/override_upd_mode so just leave it at default 0 (ie: control is on/off)

After more testing, here is my summary:
"Contrast: 7" is a special case of the eInk contrast control, in that it sets the screen to display as 1 bit (hence very dark); This is the only contrast value which doesn't flash by default.

You mention the anti-alias. What I have found is that if after a page is drawn at contrast 7, you issue the following:
echo 19 3 > /proc/eink_fb/update_display ; echo 18 0 > /proc/eink_fb/update_display ; echo 19 7 > /proc/eink_fb/update_display

the anti-aliasing fills in, and the display looks normal. this happens very fast and is not (to me) nearly as visually distracting as the normal method of refresh. the display is not perfect; you can see a slight white-ghosting of the previous page, but to me it is less obnoxious than the flash. life is all about compromises. the good news is that (for me) the ghosting is not cumulative ie: does not get worse over time; so this wouldn't require a complete refresh every 6 pages like nook does.

what we need now is for some l33t h4x0r to write a simple script to monitor page turns and issue the above command or it's equivalent. It would be a great POC if someone could just tail /var/log/messages or whatever and fire whenever the page turns.

seriously guys, this could be awesome. let's do more than change screensavers!
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Old 07-16-2011, 05:21 AM   #6
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You guys are incredible. Not brave enough to try on my own K3, but will watch this thread with interest.

Good luck, great work and THANKS!
-les
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Old 07-16-2011, 08:47 AM   #7
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looking forward to an install.bin~~thanks
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Old 07-16-2011, 08:49 AM   #8
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@khmann :



Check script from attachment.
Attached Files
File Type: zip test.zip (806 Bytes, 580 views)
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Old 07-16-2011, 08:59 AM   #9
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Guys, wish you all nothing but the best on this but the thought just crossed my mind. I am not a hardcore techie like you seem to be, but a corporate tech manager for ages so...

Having seen the video I can't help but wonder - if something like this was/appears to be [relatively speaking] "easy" to do by people without access to actual Amazon code and Kindle core HW components, it begs the question:

How come Amazon [and other eink devices makers] haven't already done it?

Surely the flashing during page changes could not possibly be considered a feature of the tech.

I only ask because the more I think about it, the more I wonder about what, if any, long-term, potentially detrimental effects this kinda non-flashing hack might have on the Kindle screens themselves?

Perhaps a stupid question as I am not hardcore techie and apologies if my concern/question is totally ignorant of the HW facts/specs involved, but any thoughts?

@khmann, totally not tying to rain on your parade here. I think this is awesome. Hope you understand where I am coming from.


-les

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Old 07-16-2011, 01:36 PM   #10
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@les, some manufacturers such as Bookeen have had a setting to turn off the flash for years now so I don't think it'll really hurt anything. It does end up causing ghosting though and I'm not sure a refresh every so many pages instead (like B&N does on the new Nook) is more desirable than just letting it refresh on every page turn. Seems to me it would be more distracting, although I don't find the current flash any more distracting than say turning a page in a pbook (ghosting can be really distracting though).

As to why someone like Amazon hasn't done it to this point it likely has to do with the number of tech support calls they'd get about ghosting (just check their CS Q&A forum to see some of the questions that get asked every day) so they'd likely want something to be "perfect" before doing it.


I love reading about the experiments folks do with their hardware like this, you never know what someone will come up with.

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Old 07-16-2011, 01:55 PM   #11
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^ Thanks a ton AnemicOak, that makes a lot of sense. I too love how much ingenuity is out there - there are indeed a ton of big brains mucking about

Personally, if I had to choose between keeping the flashing [which actually bothers me not a bit] or some ghosting on the screen [however faint]...knowing myself, I would definitely prefer the flashing.

Still, this is an extremely cool and worthwhile project.

Kudos and continued success to all involved.
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Old 07-16-2011, 11:25 PM   #12
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reflash

@seaniko7- Pimp : ) How are you using the UI to launch it?

overview, why screen flash is there in the first place:
http://www.mobileread.com/forums/sho...d.php?t=102811 has a nice discussion and mentions many of the design issues with eInk. All updates to the display are relative. Basically in eInk the only way to set the entire page to a uniformly "white" is to turn the entire thing black at once, and then clear it back to white. Because changing any pixel has a pretty strong effect on it's neighbors, modulated by relative amount of the change, and is compounded by each operation. So you lose track of the actual "displayed" value pretty quick.

What this hack is doing is using an undocumented (probably that's why no eBook maker is using it) eInk display mode to force anything over 50% to pure black and the rest to pure white. Note that it is broadstreet (or whoever) themselves that is disabling the screen flash-update in this mode, so probably it was intended for the very way we are using it (though perhaps not in a bash script : ) Since we are "splitting the difference" and going to white AND black at the same time before filling in the details, the display does a reasonable job of assembling the final image.

---------------------

Some tweaks could be made, perhaps store the default contrast (though I actually prefer it being forced to 3), and a better way to monitor when the image refresh actually occurs, but regardless

seaniko7 posted test.zip totally works... rock on!

Did I invent this? How about the name "reflash" to describe the effect as opposed to the standard flash.

Last edited by khmann; 07-16-2011 at 11:27 PM.
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Old 07-17-2011, 12:53 AM   #13
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@khmann: awesome. I am always blown away by the amount of ingenuity and technical prowess is actually out there. Gives me hope for humanity

Name: how about "UnFlash"
"NoFlashing"
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Old 07-17-2011, 03:16 AM   #14
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Here's package with launchpad and exit scripts included. Its rather for playing and testing purposes than regular usage, as it needs some improvements khmann mentioned.

http://db.tt/4godtYa
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Old 07-17-2011, 04:03 AM   #15
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Improved version of seaniko7's script.
http://pastebin.com/s8UKhNX3

I've made the page turning flash disabling more reliable, full refresh every 6 pages, won't mess up menus so bad and I've changed it to use "18 2;19 7" instead of "19 3;18 0;19 7" as I think it looks better, updates faster and isn't blurry.

Note that going backwards a page is often much slower than going forward a page and can make it look bad and the script won't do the full refresh every 6 pages if you turn a bunch of pages rapidly.

Not really sure why I did this as I think the normal is fast enough and looks much better.

The best way to make the page turning really flash-less would be to decompile the book reader, change it and recompile. Or somehow block what it's sending. (Or so I believe)
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