Tag: Nvidia

If your Linux-based PC with NVIDIA graphics started booting to a black screen or text only, here is the fix — maybe!

 

Important
This is an edited version of a post that originally appeared on a blog called The Michigan Telephone Blog, which was written by a friend before he decided to stop blogging. It is reposted with his permission. Comments dated before the year 2013 were originally posted to his blog.
Image representing NVidia as depicted in Crunc...
Image via CrunchBase

I’ve seen this happen several times now on Ubuntu-Linux based systems that have NVIDIA graphics.  What happens is that “Update Manager” pops up and tell you there are updates for your software, and you accept them.  It then tells you that your system has to be rebooted.  And when you do that, you get no video, or text only.  What probably happened was that the updates you installed included an update to the Linux kernel, and the NVIDIA graphics driver currently installed on the system was compiled against the OLD kernel.

Note that this generally can only happen if you manually updated the NVIDIA graphics driver at some point. If you always installed it from the standard repositories for your distribution, you’ll probably never see this issue. So a word to the wise — when you finally get around to doing an upgrade of your Linux distribution, try to avoid manually installing the NVIDIA graphics driver. Instead, let the distribution pull it from its repository. After that, you should not have this issue in the future. By the way, if you currently are running Ubuntu, we recommend upgrading to Linux Mint rather than a newer version of Ubuntu. Linux Mint is very similar to Ubuntu, but leaves out some of the things that users seem to hate about newer releases of Ubuntu. More to the point, they are not currently talking about switching their base graphics system from the X window server system to a new display manager, which I have a feeling might cause problems for some NVIDIA graphics users.

But if you’re not yet ready to do a full reinstall of Linux, the fix for this problem is easy IF you had the foresight to set up SSH access to your Linux system BEFORE the trouble started.  If you didn’t, and you’re not a true Linux geek, you may be kind of screwed.  So if you’re reading this and your system is working fine, and you haven’t yet set up SSH access, you may want to do that.  There are several sites that tell you how to do that; here are two that I found using Google:

Basic SSH Setup On Ubuntu 10.04 Lucid Lynx Using OpenSSH Server
SSH—OpenSSH—Configuring

If you didn’t do this beforehand, you may still be able to do it if you can get to a command prompt.

Anyway, the actual fix is to (re-)install the latest NVIDIA driver for your system. They will be compiled against the new Linux kernel and then everything should work fine. To find the correct NVIDIA driver, go to the NVIDIA Driver Downloads page, and use the dropdowns to select the correct driver for your system.  Download it to your local system, then upload it to your Linux PC (if you have SSH access working then you can use an SFTP client, such as WinSCP or Transmit, to upload your driver file).  Once you have it on your PC, from a command prompt navigate to the directory where you put the driver and then change the permissions to make it executable:

sudo chmod +x driver_upgrade_script_filename

Now try running the script (it should have a .run extension):

sudo ./driver_upgrade_script_filename

It should not complain that the Gnome Display Manager or KDE Display Manager is running (if it were, you wouldn’t be in a state of near-panic right now), but if you were just doing a regular update you’d have to do this when the GDM/KDM is stopped. For a guide that covers that scenario, see How To Install Official Nvidia Drivers in Linux, or just know that to stop the display manager,

sudo /etc/init.d/gdm stop

should stop the Gnome Display Manager, or if you’re using KDE then the command would be

sudo /etc/init.d/kdm stop

Most sources I’ve seen suggest that you answer yes to any questions the installer may ask. The only one I’d be cautious about is letting it create a new xorg.conf if you are using a customized one (which you may well be if you’ve used any of my previous HTPC-related articles). If you have edited xorg.conf, then I’d make sure you at least have a backup before letting the installer create a new one, so you can revert back to your custom one (or compare the two and insert your customizations into the new one) if necessary.

Under Ubuntu, you may get a message similar to “Provided install script failed”. That will happen every time you update the NVIDIA driver this way and it is normal. Just ignore it and continue the installation. If you get “Error locating kernel source”, run  sudo apt-get install kernel-source  from the command prompt, then run the driver upgrade script again.

When the installer has successfully finished, reboot the system and when it comes back up, hopefully you should be happy again!

An overscan fix for the Sharp LC-42SB45U television set when connected to a computer with a Linux operating system (Ubuntu, etc.)

 

Important
This is an edited version of a post that originally appeared on a blog called The Michigan Telephone Blog, which in turn was reposted with the permission of the original author from a now-defunct Macintosh-oriented blog. It is reposted with his permission. Comments dated before the year 2013 were originally posted to The Michigan Telephone Blog.

If you bought a Sharp LC-42SB45U TV, perhaps because it was on a super great (and very lightly advertised) deal at Wal-Mart back in November, and then later tried to hook up a home theater PC to it, you may have been disappointed to discover that unlike most flat screen digital TV’s it doesn’t have a “pixel-to-pixel” or similar 1:1 pixel mapping mode. The result is that when you hook up a computer to one of the HDMI ports, there is a serious overscan problem — for example, if you are running Ubuntu Linux (or some other version of Linux) you won’t see the top or bottom menu bars, because they are outside the visible screen area. If you use XBMC or Boxee, you can go into that program’s settings menu and apply overscan correction from within the program, but most other programs and video players don’t offer an overscan correction option.

The problem is not that there’s no “Dot by Dot” setting in the Sharp TV — it’s just that it’s a (very) hidden option, and as far as I know, there is nothing you can do using the buttons on the TV or on the remote to make it appear (I’d be very happy to be proven wrong on this point; if there is some sort of hidden remote control key sequence that can make the Dot by Dot option always appear, I wish someone would spill the beans so we can fix this issue the right way). But with one small tweak in a Linux configuration file, you can make it appear, like so:

Sharp LC-42SB45U TV showing Dot by Dot option

My first approach to this came at a cost: I read that if you could send the Sharp a non-standard vertical sync frequency (refresh rate) a bit below the normal 60 Hz, the alternate View Mode would appear.  That did work, and in my non-scientific testing, I found that 59.55 Hz was about the cutoff point.  Anything above that, and you get the normal menu of View Mode options when you press the View Mode button on the remote.  Anything at about that or below,  and you get the View Mode options menu shown above. However, this was certainly less than ideal because of the non-standard refresh rate. I got started on that path after reading a forum post that suggested a custom ModeLine in your /etc/X11/xorg.conf file to give you a 1816×1026 display.  While this will work to fix the overscan, it also cuts down on the pixels available to programs, and makes things not quite as sharp (no pun intended) as they should be.

Now, the idea of using a custom ModeLine in your /etc/X11/xorg.conf file is not a bad idea, and the above-referenced post did contain some good information  (especially about disabling some unwanted Ubuntu packages that might cause your xorg.conf to be ignored).  So I tried the xorg.conf shown in that post, except I used the original ModeLine shown (which is correct for the Sharp LC-42SB45U as long as you don’t mind the overscan).  I then read in another forum post (on a different site) that someone had found that the Dot by Dot option would appear if the refresh rate were set to 59 Hz rather than 60 Hz.  However they were doing that on a Windows machine, not a Linux box, if I recall correctly.

But again, that had the disadvantage of a non-standard refresh rate.  I’ve read on several sites that the ideal refresh rate is 59.94 Hz (it’s very close to 60 Hz and is exactly twice the ATSC 1920×1080 progressive scan frequency of 29.97 Hz) so my goal was to get as close to that as possible. I then read that someone had actually accomplished this on a Windows box by changing the timing to something called “CVT reduced blank” (the procedure on a Windows box is to bring up the NVIDIA Control Panel, then click on Change Resolution, then Add Resolution, then Create Custom Resolution, then in the “Timing” section find the “Standard” drop-down box and select CVT reduced blank. Make sure the other settings look sane, click the Test button and go from there. Mac OS X users can do something similar using a program called SwitchResX — see Brian Semiglia’s comment in the Comments section for a link to instructions. The reason this doesn’t work under Linux is that the Linux version of the NVIDIA Control Panel doesn’t offer this level of functionality, and also, some might encounter this issue even if not using NVIDIA graphics). So my goal was to find a ModeLine that would do the CVT reduced blank but not use a non-standard screen size nor refresh rate. After searching the web, playing around with an online Calculator for video timings which I saved to a local drive and then hacked a bit to display four decimal points of precision on some key values, and generally spending more time than I intended, I came up with a working ModeLine.

First, let’s look at the original 1920×1080 ModeLine from the above-linked forum post:

ModeLine "1920x1080" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync

If you change the pixel clock frequency value in a ModeLine (the 148.50 in the line shown above) you change the refresh rate, and if you change certain other values you change the other timings.  I cheated a bit and used Google to search for a working ModeLine that provided 1920×1080 at 59.94 progressive scan, and found one that was very close (59.93, actually) so I tweaked the refresh to give me exactly 59.94.  This is the final ModeLine I came up with:

Modeline "1920x1080" 138.5141 1920 1968 2000 2080 1080 1083 1088 1111 +hsync +vsync

Okay, so you may think it ridiculous to specify the pixel clock frequency out to four decimal places, but hey, it works! So, this is what I’m now using for an xorg.conf file (by the way, if any of the ModeLines in this article are truncated on your display, just keep in mind that the last two values in each line are +hsync +vsync — if you copy and paste any of the long ModeLines, hopefully you’ll get the complete line).  Bear in mind that I’m using this with an Acer Aspire Revo, so some of these lines are specific to the NVIDIA graphics chipset, but the principle of changing the ModeLine probably should work with this model Sharp TV even if some other graphics chipset is used on the computer:

# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 1.0  (buildmeister@builder75)  Tue Dec  8 21:04:28 PST 2009

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
EndSection

Section "Files"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/psaux"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Unknown"
    HorizSync       15.0 - 75.0
    VertRefresh     55.0 - 76.0
    ModeLine       "1920x1080" 138.5141 1920 1968 2000 2080 1080 1083 1088 1111 +hsync +vsync
    Option         "ExactModeTimingsDVI" "TRUE"
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    Option         "ModeValidation" "NoEdidModes"
    Option         "HWCursor" "false"
    Option         "DynamicTwinView" "false"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    SubSection     "Display"
        Modes      "1920x1080"
        Depth       24
    EndSubSection
EndSection

Section "Extensions"
     Option         "Composite" "Disable"
EndSection

This seems to work well on a Acer Aspire Revo running Ubuntu Karmic Koala (EDIT: and I’ve also used it under Maverick Meerkat), though I imagine it would work with other Linux distributions that use an xorg.conf file (including XBMC Live), however as far as I know this trick only works with the Sharp LC-42SB45U TV and no other model.  With this xorg.conf I don’t have to tweak the overscan settings in XBMC or Boxee at all. It works for me, but it may or may not work for you.  Standard disclaimers apply – I’m not telling you to do this on your setup, and if you break something, you own all the pieces, but from me you’ll get nothing more than perhaps a bit of sympathy. Don’t even think of doing this if you are not willing to assume any and all risks.

EDIT: If you don’t want to go through all the hassle I went through to calculate the correct ModeLine, you can run the cvt program with the -r option from the Linux command prompt, like this:

cvt -r 1920 1080

That’s for a 1920 x 1080 display. On my system this generated the following output:

# 1920x1080 59.93 Hz (CVT 2.07M9-R) hsync: 66.59 kHz; pclk: 138.50 MHz
Modeline "1920x1080R"  138.50  1920 1968 2000 2080  1080 1083 1088 1111 +hsync -vsync

You’ll notice this is nearly identical to the ModeLine I generated (the vsync is the opposite, though — don’t know if that would be an issue). What I’ve read is that you paste the generated ModeLine into your xorg.conf file and make sure you also have the line

Option         "ExactModeTimingsDVI" "TRUE"

in your xorg.conf (to force it to use your generated ModeLine) and that may be all you need. Certainly simpler than how I did it, but I didn’t know about the cvt program. (End EDIT).

By the way, if you want to hack that Calculator for video timings, just save the HTML page to your local hard drive, open it in a text editor and look for this section (it’s very close to the top):

function TwoDecimal(number) {
 number=((Math.round(number*100)/100));
 return number;
}

Change that second line to

number=((Math.round(number*10000)/10000));

Then load the page into your favorite browser (with JavaScript enabled). That will display a couple extra decimal points on some of the critical values.

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