Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 
  2 Some hints to get the bttv driver up and running
  3 ================================================
  4 
  5 general hints
  6 -------------
  7 
  8 (1) Make sure if your board is recognized correctly. The bttv driver
  9     should print a line like this one (Use the 'dmesg' command to see
 10     the kernel messages):
 11 
 12         bttv0: model: BT848(Hauppauge old)
 13 
 14     If your card isn't autodetected correctly, you have to specify the
 15     board type as insmod argument (card=n).  You might also have to
 16     specify tuner=x and pll=x.
 17     Check the driver documentation for details and a list of supported
 18     cards.  The standard kernel has the bttv documentation in the
 19     Documentation/video4linux/bttv directory.
 20 
 21 (2) If you are using a vanilla 2.2.x kernel kernel, it is worth trying
 22     to upgrade as the very first step.  Either download and build bttv
 23     0.7.x for your 2.2.x kernel, or upgrade to 2.4.x which includes
 24     the 0.7.x driver already.
 25     bttv 0.7.x knows a lot more cards than the 2.2.x kernel driver, the
 26     autodetect is much improved and a number of known problems is
 27     fixed.
 28 
 29 (3) If you have problems with xawtv, you should open a xterm (or
 30     whatever your favorite terminal app is) and start xawtv from
 31     there. This way you'll see any error messages xawtv might print on
 32     stderr which should help to find the source of the problems.
 33 
 34 (4) If something broke after an update, have a look at the changelog.
 35     It might be mentioned there.
 36 
 37 
 38 common problems
 39 ---------------
 40 
 41 ?: I have a black screen in overlay mode
 42 !: The driver was not initialized correctly, v4l-conf (or the
 43    X-Server) has to configure the bttv driver with the current video
 44    mode and framebuffer address first.  Check if v4l-conf is installed
 45    suid root, it needs root priviliges to do this.  You can also start
 46    v4l-conf from a terminal and check the messages it prints.
 47 
 48 ?: I have a blue screen.
 49 !: Good, the overlay is working.  A blue screen is what you get if the
 50    grabber chip has no input signal.  You are probably using the wrong
 51    video source, pick another.  Also happens sometimes if the tuner
 52    type is wrong, check the driver configuration.
 53 
 54 ?: I have a noisy screen and/or can't tune (some) stations.
 55 !: Most likely the tuner types is wrong, check the driver configuration.
 56    It's no problem to do trial-and-error here.
 57 
 58 ?: The video is outside the window and spread in thin lines over the
 59    screen.
 60 !: xawtv / v4l-conf didn't autodetect the color depth for your screen
 61    correctly.  You can fix that with xawtv's -bpp switch.
 62 
 63 ?: Only the left part of the window is updated, the right one is updated
 64    never / sometimes / only if the window is small.
 65 !: Your graphics card and/or motherboard can't deal with the data rate
 66    going over the PCI bus, leading to canceled PCI transfers.  Reduce
 67    the color depth, with 16 bpp instead of 32 bpp should work much
 68    better.
 69 
 70 ?: I get no sound.
 71 !: (a) If your TV-Card is connected to the sound card's line in with a
 72        short cable: Make sure the sound driver is loaded, sound cards
 73        are usually quiet until initialized by the driver.  Also check
 74        the mixer settings.
 75    (b) Double-check the card type is correct (see above).
 76    (c) If there is still no go, have a look at the Sound-FAQ in the
 77        bttv documentation.
 78 
 79 
 80 hardware specific problems
 81 --------------------------
 82 
 83  * bttv + DRI seem not to play nicely together with some cards (ATI
 84    Rage128).  The linux box just freezes.  Don't know why.  Suspect
 85    it's either a hardware problem or a bug somewhere in DRI (either
 86    kernel or xfree86).  The only workaround I know of is to turn off
 87    DRI.
 88 
 89  * Some motherboard chipsets have PCI bugs, especially with PCI-PCI
 90    transfers which are used for video overlay.  The bt848/878 chips
 91    have some bug compatibility options, which can be enabled to
 92    workaround these problems.  Have a look at the triton1 and vsfx
 93    insmod options.  For some known-buggy chipsets these are enabled
 94    automagically.
 95 
 96  * Sometimes IRQ sharing causes trouble.  It works most of the time,
 97    but in combination with some hardware and/or drivers it doesn't work.
 98    Especially graphic cards are known to cause trouble due to the lack
 99    of a IRQ handler.  Try disabling the VGA IRQ in the BIOS.  Try moving
100    cards to another PCI slot.  Your motherboard manual should tell you
101    which PCI slots share IRQ's.
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