# Missed Keystrokes

## r00t440

I have a cheap laptop with an unknown brand, there seems to be a problem with the way it handles keyboard input.

Here's how it behaves:

When typing it seems to sporadically skip characters. Example, if I type "Hello" there's a chance that the entered text just becomes "Hllo". I tried the following without luck:

* Different distros - I tried SystemRescueCD; Funtoo; Ubuntu; Different flavors of Sabayon 

* An external USB keyboard

* Toggling ACPI during boot and some IRQ tricks I found from other forums

Some success:

Few months back, the symptom doesn't seem to exist on 32-bit Sabayon (64-bit versions always have the problem), however after several updates (also updated the kernel), the symptom re-emerged. In windows everything works fine so my guess is that this laptop uses some sort of low quality "keyboard controller" - not sure what's the term. It seems that its "input buffer" is buggy - at least on 64bit Linux. 

I hope somebody can point to me which kernel option I should check or experiment with - I am comfortable to compiling the kernel (been doing it for like 10 years already). Probably some kernel options cause this behavior.

Laptop Specs:

 *Quote:*   

> Intel Core i7-2630QM
> 
> 6 MB, 2.0 GHz
> 
> Intel HM65
> ...

 

Thanks in advance

** I've also posted this in: https://forum.sabayon.org/viewtopic.php?f=56&t=29577

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## Budoka

 *r00t440 wrote:*   

> I have a cheap laptop with an unknown brand, there seems to be a problem with the way it handles keyboard input.
> 
> Here's how it behaves:
> 
> When typing it seems to sporadically skip characters. Example, if I type "Hello" there's a chance that the entered text just becomes "Hllo". I tried the following without luck:
> ...

 

Are the letters that are getting dropped consistently the same? It could be something as simple as a dirty keyboard.

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## verchiel

Well, r00t440 claimed to have tried an external keyboard, so dirt in the keyboard shouldn't be an issue. I would rather check the BIOS settings again and look for anything keyboard related as well as USB settings. Can you tell us your BIOS name/version (and maybe search for known issues as well)? And maybe be so kind and look for information on the mainboard and/or vendor information on the laptop, even if the brand is less well-known... what is its name anyway (model/vendor)? Or, if that information is unavailable, where did you buy it / do you have a link to the product? If it is really an OS problem then I'd rather guess it's about the mainboard/chipset. In many cases laptop keyboards are connected through PS/2 ports rather than USB though. Are you experiencing any other issues?

Cheers

Dan

Addendum: From the information you provided, it sounds pretty much like a Basic B57xx series model from the Neo brand. Just a guess.Last edited by verchiel on Mon Apr 08, 2013 4:52 am; edited 2 times in total

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## Budoka

 *verchiel wrote:*   

> Well, r00t440 claimed to have tried an external keyboard, so dirt in the keyboard shouldn't be an issue. I would rather check the BIOS settings again and look for anything keyboard related as well as USB settings. Can you tell us your BIOS name/version (and maybe search for known issues as well)?
> 
> If it is really an OS problem then I'd rather guess it's about the mainboard/chipset. In many cases laptop keyboards are connected through PS/2 ports rather than USB though. Are you experiencing any other issues?
> 
> Cheers
> ...

 

Whoops. I missed that.

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## verchiel

And just another guess... the backspace key might be malfunctioning. You could try disabling your PS/2 keyboard in the BIOS setup and see if it works fine if you use only your USB keyboard instead. Just another guess.  :Smile:  And if there is no such option... well, I have to hint you that it might mean losing warranty, but I would open the laptop and unplug the keyboard. Or even unsolder if necessary. I don't recommend that though. ^^

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## r00t440

 *verchiel wrote:*   

> Well, r00t440 claimed to have tried an external keyboard, so dirt in the keyboard shouldn't be an issue. I would rather check the BIOS settings again and look for anything keyboard related as well as USB settings. Can you tell us your BIOS name/version (and maybe search for known issues as well)? And maybe be so kind and look for information on the mainboard and/or vendor information on the laptop, even if the brand is less well-known... what is its name anyway (model/vendor)? Or, if that information is unavailable, where did you buy it / do you have a link to the product? If it is really an OS problem then I'd rather guess it's about the mainboard/chipset. In many cases laptop keyboards are connected through PS/2 ports rather than USB though. Are you experiencing any other issues?
> 
> Cheers
> 
> Dan
> ...

 

Wow, your guess is accurate. It's indeed a B5700N laptop. You must be from PH?

 *verchiel wrote:*   

> And just another guess... the backspace key might be malfunctioning. You could try disabling your PS/2 keyboard in the BIOS setup and see if it works fine if you use only your USB keyboard instead. Just another guess.  And if there is no such option... well, I have to hint you that it might mean losing warranty, but I would open the laptop and unplug the keyboard. Or even unsolder if necessary. I don't recommend that though. ^^

 

No, backspace is working perfectly fine. With regards to disabling PS/2 keyboard in BIOS, I'm not sure if I can do that, laptops normally have limited options in BIOS that you can tweak. How is that different with using an external keyboard? I'm at work atm and I can't access my laptop so I'll try your suggestion when I get back home this weekend. 

With regards to the idea of unplugging the keyboard, won't be a problem because it's already out of warranty. If it fails, then I think I'll just buy a Windows license.

Thanks Budoka and verchiel for taking the time to reply, I appreciate it - gives me some hope.

Cheers

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## r00t440

Unable to solve this problem. I hope somebody out there can shed some light with this issue.

Issue doesn't exist in Window$.

TIA

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## teika

I'm completely clueless, but is it only in X, or in consoles, too?

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## r00t440

Hi teika, thanks for replying. 

I'm clueless as well, all I have are symptoms of the problem. I think the best way forward is to just live with this issue, I'm thinking of utilizing this notebook as an HTPC.

Kind regards

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## Ant P.

Does this happen if you temporarily disable some of the extended powersaving features? I've seen similar things happen on an AMD CPU with C1E enabled and a Celeron with CONFIG_NO_HZ.

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## r00t440

 *Ant P. wrote:*   

> Does this happen if you temporarily disable some of the extended powersaving features? I've seen similar things happen on an AMD CPU with C1E enabled and a Celeron with CONFIG_NO_HZ.

 

Hi Ant P. thanks for the idea, can this be configured during boot? - I'll google it.  :Very Happy: 

Thanks

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