Do Sager laptops have keyboard ghosting problems?

I'm looking for a new laptop and I'm interested in the Sager 8150 and 7282. After reading this thread http://forum.notebookreview.com/alienware-m18x/583019-m18x-keyboard-multiple-keys.html about keyboard ghosting, I'm curious if any Sager laptops have had similar problems.

 

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^ was the above problem noted in the thread you saw. As far as ghosting goes im a SC2 and rts player... If I don't have any ghosting problems I'm pretty sure your good. But just to test it out...

asfd asfd dasfh dasfj sfd

^ went from 4 first then the next 4 sets are with 5 keys pressed.

Now purely 6 keys
fasd fasd saf fas sa asf

seems sager can go safely 4 keys pressed at a time.

 

I have a support ticket in atm with XoticPC; there are some combinations that don't work over 2 keys (rare), most appear to be between 3 to 6 keys.

Kind of sucks, but I've been able to remap around the only 2-key combinations. Hopefully there is a fix for it (seems like an EC firmware issue).

 

If the keyboard operates on the USB bus, you will never be able to press more than 6 at a time. If it's PS2, then there should be no reason why there would be a limit on the number of key presses.

 

I'm fairly certain my keyboard doesn't have ghosts.

 

Snip and Edit... need to research something I thought was cut and dry.... don't mind this

Also, owners who think they don't have this issue, try typing to following while holding both shift keys (left and right)...

Code:

The quick fox jumped over the lazy dog.

Wish we had a spoiler tag, but I'll go ahead and say it. If your sentence ends up having spaces in it, you didn't hold down both shift keys while typing. Left Shift + Right Shift is a combination that prevents detection of the space bar press (also won't detect either control or alt key, as well as the ` key)

 

That's pretty neat. I just tried that on my Qosmio and it doesn't create spaces.

 

wow, that cut off my ability to use like half of my keyboard.

 

HE QUIK BROWN FO JUPS OER HE LA DOG>

6 year old unbranded wireless keyboard that came with the pc. Modern expensive keyboards can't do any better? Why can't they fix the problem?

 

Because it's a limitation of the USB bus. Nothing OEMs can do about it.

 

There's three references at the bottom of this post. They will give you a headache, but they clear up some things. The 6 non-modifier key/4 modifier key limit on the USB bus is not the issue here.

The issue we're seeing is some odd combinations just don't work, probably to prevent ghosting (despite Microsoft's definition, it's when a key you didn't press shows up, not when a key in a combination does not show up... ). These key presses (such as W+A+G or W+D+G, or even L Shift + R Shift + Space) are well under the the USB limitation (first two are 3 non-modifier, second is 2 modifier + 1 non-modifier) and what we could be seeing is either a limitation imposed by hardware (isolating diode, etc) to prevent ghosting or a possible bug/anti-ghosting limitation in the BIOS/EC that can be patched and still prevent ghosting.

Or a third explanation that I'm not thinking of because I don't venture that deep; I try to stick to the software and operating system layers, people who went to college longer than I did can deal with the drivers and BIOS .

Supplemental Reading
Wikipedia: Rollover (key)
Microsoft Applied Sciences Group: Keyboard Ghosting Explained!
ControlSpace: n-Key Rollover

 

FYI: the keyboard is PS/2 in these laptops, not USB, The trackpad is also PS/2.

Quite a lot of laptops still use PS/2 for the mouse and keyboard interface, theres a few out there using USB but it's not uncommon by any means to find PS/2.

 

That's what I thought and further drives the nail that this is not a bus limitation issue.

Wasn't sure if the keyboard on this was true PS/2 interface or PS/2 through the USB bus... thanks for the heads up.

 

What do you mean limitation of the USB bus? USB isn't the problem, it's the interpretation of the codes. I mean you can send data from multiple devices at up to 480Mbps, sending multiple keyboard keystrokes shouldn't be a problem.

 

From one of the links CoderJ posted:

I was misunderstanding the issue. What they're talking about is something unrelated to the USB limitation. It's also irrelevant because the keyboards are on the PS2 interface.

 

Two things:

First, I got a response back today from tech support. I don't think we're allowed to C&P the e-mails here but in a nutshell I was told that the combinations that do not work are a limitation of the hardware and can not be addressed through a BIOS/EC update nor a swap of the keyboard. So that's life, luckily the issue seems isolated to small sets of keys so it's easy enough to remap some bindings around if it is encountered.

-=-=-=-
This gets techincal; I went cross-eyed a few times (I don't work at or below the OS layer). If you can understand this stuff better or know someone who can... like an actual USB hardware engineer... please feel free to call me an idiot and correct me.

As to why, on USB, key strikes are limited to 6 non-modifier and 4 modifier... the answer is here (pdf), in the Device Class Definition for HID 1.11 published by the USB Implementers Forum (creators and maintainers of the USB standard). Basically, the keyboard interrupt packet is 8 bytes long:

Code:

Byte 0 = Modifier Key(s)
Byte 1 = RESERVED
Byte 2 = Keycode
...
Byte 7 = Keycode

Per the HID 1.11 standard, this is the packet which is to be expected by the system when it polls the USB interrupt_in report (that is, data sent from the device unsolicited by the system). At least, that is my understanding. Read the standard, google, maybe order some stuff and try making your own keyboard (there are ways around the 8-byte packet, I believe that is only required of boot device keyboards; my understanding is once in the OS it is possible to increase poll rate of interrupt_in and use a different report to read the keypresses)

I'm (not) Cave Johnson, we're done here.