Display and keyboard issues (on a real Pi)


17 posts
by Alun » Sun May 06, 2012 8:38 am
Received my real Pi yesterday & loaded the Debian image. Boots OK but when connected to a Sony 32" TV (1366x768 but I would have to take the TV off the wall to find the model number) the picture is much smaller than the screen (say 15% smaller all the way round). The TV reports the correct signal at 1366x768 @ 60Hz. I also compiled and loaded the 30/04 build of OpenElec & put it onto another SD card - the display from OpenElec is OK and fills the screen.

On another subject, my Pi does not work with a Microsoft wireless keyboard 800 (which was the spare unit I had lying around). With this keyboard it either does not register key presses or registers random ones - it was so bad that I could not log in then the unit crashed while filling the screen with the letter "p" as I tried to type "pi". The Pi does work fine with a Globlink GKM-700 wireless keyboard (http://globlink.en.ecplaza.net.....06172.html). The Microsoft keyboard works OK with other PCs.

I am an experienced Linux user and system administrator but have not had time to investigate either issue properly yet.

Has anybody else had similar issues on a real Pi?
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by Alun » Sun May 06, 2012 8:41 am
Sorry – I meant to post this in the Debian section - that was where I was reading when I started the post. Please move the post.
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by dom » Sun May 06, 2012 9:25 am
create a file /boot/config.txt containing:
disable_overscan=1

The keyboard uses too much current to be directly connected to Pi. Use a powered USB hub or a different keyboard.
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by tufty » Sun May 06, 2012 9:36 am
dom said:


The keyboard uses too much current to be directly connected to Pi. Use a powered USB hub or a different keyboard.


I suspect it's more likely to be the wireless dongle than the keyboard that's pulling too much juice.  That or some other USB peripheral.  The hint is in the name.


Microsoft wireless keyboard 800


Alun - are you using the same dongle between the two keyboards?
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by Alun » Sun May 06, 2012 10:25 am
Thanks for the replies - each keyboard has its own dongle. I suspected it may be a power issue but the Microsoft dongle has 5V 50mA written on it which should be OK. The unit that works is a multimedia keyboard designed to be used across a room so I suspect may take more power - the dongle is about 20x the physical size of the Microsoft unit but does not have anything written on it.

I'll try the overscan bit & report back.
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by Alun » Sun May 06, 2012 11:35 am
The overscan bit worked great thanks dom.

For anyone unfamiliar with Linux the file can be created from the command line by:

sudo nano /boot/config.txt

Unless you have set a root password the default appears to be blank therefore it should just work. Instructions on setting a root password are here:

http://www.raspberrypi.org/for.....n-password

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by Alun » Mon May 07, 2012 12:43 pm
After wrestling with the search "feature" of this forum I have found a number of other references to the same problem with a Microsoft Wireless Keyboard 800.

It appears not to work so until I get time to investigate why I'll use in on my Linux Mint 12 machine and use the Globlink keyboard for the Pi.
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by gruffman » Mon May 07, 2012 5:33 pm
I have a logitech Illuminated keyboard it's rated 5v and 300mA.

I also use a 5v 750mA power source for my Pi.

The pi senses the key strokes, but will often hold the last hitted key down, so it seems to be a problem with this keyboard, even though I have turned the lights off.
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by SN » Mon May 07, 2012 8:04 pm
300mA is your problem – way over the raspi usb limit
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by gruffman » Tue May 08, 2012 7:59 pm
SN said:


300mA is your problem – way over the raspi usb limit



Thought so, brought a basic keyboard still rated 100mA but works with no issues
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by gruffman » Tue May 08, 2012 8:04 pm
Another problem, the pi does'nt seem to understand my monitor. It worked great at my Sony 40" tv with hdmi cable. Now I bought a hdmi to dvi adapter for my benq monitor, first of all I got all these green dots all over the screen where the text appears. Then when I manage to go inte Xwin I can really see that the pi did'nt understand my monitor settings. The graphical desktop is much smaller than It should be.

Any suggestions?
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by Steady_Bear » Tue May 08, 2012 8:16 pm
Please read the following post:

http://www.raspberrypi.org/for.....corruption

Also, have a look about for overscan / underscan etc in the forums. The screen being smaller than expected has been done to death ;P . It is intentional, and it is adjustable to output to how you'd expect it to be. config.txt is your friend.

Should be the same problem you are having. I'll not rewrite the solution as it's always better to not start a game of Chinese whispers*.

*of course, no disrespect intended ;)
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by gruffman » Tue May 08, 2012 10:05 pm
thanks alot!!

This solved it:

config_hdmi_boost=4

disable_overscan=1
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by Richard ST » Sat Jul 07, 2012 12:21 pm
Hello All,

I am running debian6-19-04-2012 on a SanDisk 4GB SDHC 30MB/s.

I also had trouble with a Microsoft Wireless 800 keyboard, even when the dongle was connected to a powered hub. It either missed keystrokes or repeated them. I guess that the repeats are due to the driver not seing a 'key released' message.

A Dell SK-8115 keyboard (borrowed from work) works fine, whether in the hub or by direct connection. It is rated at 100 mA but may well draw less.

A PC World esssentials keyboard always causes a kernel panic as soon as it is connected to the hub. It is rated at 50 mA. The keyboard works fine on a Toshiba WinXP laptop.

I guess that there may be a keyboard driver problem.

My monitor is a Toshiba LT22A350 monitor/TV connected on HDMI. It runs at its native 1920x1080p 60 Hz in text mode at startup. LXDE shows the resolution to 1824x984 (as reported by LXRandR 0.1.1), although the monitor is still seeing 1092x1080p 60 Hz. The fonts do appear to be slightly re-sampled so I am not sure if all is quite correct. I see that there is a beginner's FAQ on this, so I'll look into the issue.

Win32 disk imager failed to see the SD card when it was mounted in the built-in slot in my oldish Tosh XP sp3 laptop. I tried flashnul-1rc1, it saw the SD card and reported success at transferring the debian image. But the R-Pi didn't do anything - the SD card image was faulty.

However, Win32 disk imager worked correctly on a Win7-64 laptop.

At present my Pi is running at TP1-TP2 = 4.57 V, powered from a Cerulian N10JB 4-port USB hub with a 5V 2A rated PSU, with LDXE running but idle. The input to the hub is 5.16V. The hub drops this to 4.82 V on its USB A sockets via a diode. The hub-to-Pi micro USB cable and polyfuse drop the remaining 0.25V.

I tried another micro USB cable. The Pi seemed fine but TP1-TP2 was just 3.8 V. This cable is marked 28AWG but the resistance on the 5V line is about 5 ohms!. No wonder my phone was taking a while to charge.

I have compiled and run a canonical 'Hello.c' on the Pi. That is about the extent of my Linux knowledge.

Have fun, all.
Richard
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by KeithR » Fri May 24, 2013 2:53 pm
Sorry to wake an old post but I thought it should be updated given the eLinux.org "R-Pi Troubleshooting" guide (http://elinux.org/R-Pi_Troubleshooting#Wireless_Keyboard_trouble ) cites this discussion specifically regarding the Microsoft Wireless Keyboard 800 having issues:
Wireless Keyboard trouble
Some wireless keyboards, for example the Microsoft Wireless Keyboard 800 are reported to fail[12] even though the current drawn by the wireless adaptor is within the R-Pi USB spec limit of 100 mA. This may be a software driver problem.


I can add to this now to confirm that the dwc_otg.speed=1 work-around does also work specifically for the Microsoft Wireless Keyboard 800 - though at the cost of forcing USB 1.1 for all usb devices as noted by efflandt:

efflandt wrote:A common solution for dropped or sticky keys or dropped mouse clicks is to add dwc_otg.speed=1 to the end of the line in /boot/cmdline.txt. But that has to remain one long line (make sure it does not wordwrap). The problem is apparently sensing key down and key up events (split transactions) depending upon what all you have connected to USB and how it is connected.

Note that this forces USB 1.1 which may slow networking and external USB flash or disk access, but at least it fixes dropped or repeated keys that make it difficult to blindly enter passwords with no feedback.
[Above quote taken from this this discussion http://www.raspberrypi.org/phpBB3/viewtopic.php?f=63&t=27099#p244250 relating to same problem for a different keyboard.]

Using the above work-around I can now use my Microsoft Wireless Keyboard 800 without any problems of keystrokes missing and without any keys randomly repeating. Downside is USB will be slower - but pick your trade off between that and a new keyboard (hopefully just for the time being until a proper solution can be found).

N.B. I'm using Arch Linux ARM (a.k.a. alarmpi) with fully up to date system.
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by dom » Fri May 24, 2013 3:51 pm
You could try:
viewtopic.php?f=28&t=39175&start=25#p345905

which is a fix that doesn't require low speed usb (although still undergoing testing).
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by KeithR » Wed May 29, 2013 12:51 pm
dom wrote:You could try:
viewtopic.php?f=28&t=39175&start=25#p345905

which is a fix that doesn't require low speed usb (although still undergoing testing).


Thanks dom for the pointer to the USB FIQ driver discussion. Some excellent work being done there!

I'm using Arch Linux ARM but I see the rpi-update package is maintained only for Raspbian. Can anyone using alarmpi vouch for a good (step by step) tutorial for manual firmware upgrade on Arch Linux ARM from hexxeh's github source?

Note: I know about + tried the "rpi-update-git" package someone put on AUR (the Arch User Repository) but one of the dependencies failed to build in a way that seemed not worth pursuing. That (plus several comments read elsewhere) made me think I'd be better doing a "simple" one-off manual firmware update from hexxeh github source. Please feel free to point me in the right direction if there is a better option I should be looking into instead.
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