CyBlaFB is a framebuffer driver for the Cyberblade/i1 graphics core integrated into the VIA Apollo PLE133 (aka vt8601) south bridge. It is developed and tested using a VIA EPIA 5000 board. Cyblafb - compiled into the kernel or as a module? ================================================== You might compile cyblafb either as a module or compile it permanently into the kernel. Unless you have a real reason to do so you should not compile both vesafb and cyblafb permanently into the kernel. It's possible and it helps during the developement cycle, but it's useless and will at least block some otherwise usefull memory for ordinary users. Selecting Modes =============== Startup Mode ============ First of all, you might use the "vga=???" boot parameter as it is documented in vesafb.txt and svga.txt. Cyblafb will detect the video mode selected and will use the geometry and timings found by inspecting the hardware registers. video=cyblafb vga=0x317 Alternatively you might use a combination of the mode, ref and bpp parameters. If you compiled the driver into the kernel, add something like this to the kernel command line: video=cyblafb:1280x1024,bpp=16,ref=50 ... If you compiled the driver as a module, the same mode would be selected by the following command: modprobe cyblafb mode=1280x1024 bpp=16 ref=50 ... None of the modes possible to select as startup modes are affected by the problems described at the end of the next subsection. For all startup modes cyblafb chooses a virtual x resolution of 2048, the only exception is mode 1280x1024 in combination with 32 bpp. This allows ywrap scrolling for all those modes if rotation is 0 or 2, and also fast scrolling if rotation is 1 or 3. The default virtual y reso- lution is 4096 for bpp == 8, 2048 for bpp==16 and 1024 for bpp == 32, again with the only exception of 1280x1024 at 32 bpp. Please do set your video memory size to 8 Mb in the Bios setup. Other values will work, but performace is decreased for a lot of modes. Mode changes using fbset ======================== You might use fbset to change the video mode, see "man fbset". Cyblafb generally does assume that you know what you are doing. But it does some checks, especially those that are needed to prevent you from damaging your hardware. - only 8, 16, 24 and 32 bpp video modes are accepted - interlaced video modes are not accepted - double scan video modes are not accepted - if a flat panel is found, cyblafb does not allow you to program a resolution higher than the physical resolution of the flat panel monitor - cyblafb does not allow vclk to exceed 230 MHz. As 32 bpp and (currently) 24 bit modes use a doubled vclk internally, the dotclock limit as seen by fbset is 115 MHz for those modes and 230 MHz for 8 and 16 bpp modes. - cyblafb will allow you to select very high resolutions as long as the hardware can be programmed to these modes. The documented limit 1600x1200 is not enforced, but don't expect perfect signal quality. Any request that violates the rules given above will be either changed to something the hardware supports or an error value will be returned. If you program a virtual y resolution higher than the hardware limit, cyblafb will silently decrease that value to the highest possible value. The same is true for a virtual x resolution that is not supported by the hardware. Cyblafb tries to adapt vyres first because vxres decides if ywrap scrolling is possible or not. Attempts to disable acceleration are ignored, I believe that this is safe. Some video modes that should work do not work as expected. If you use the standard fb.modes, fbset 640x480-60 will program that mode, but you will see a vertical area, about two characters wide, with only much darker characters than the other characters on the screen. Cyblafb does allow that mode to be set, as it does not violate the official specifications. It would need a lot of code to reliably sort out all invalid modes, playing around with the margin values will give a valid mode quickly. And if cyblafb would detect such an invalid mode, should it silently alter the requested values or should it report an error? Both options have some pros and cons. As stated above, none of the startup modes are affected, and if you set verbosity to 1 or higher, cyblafb will print the fbset command that would be needed to program that mode using fbset. Other Parameters ================ crt don't autodetect, assume monitor connected to standard VGA connector fp don't autodetect, assume flat panel display connected to flat panel monitor interface nativex inform driver about native x resolution of flat panel monitor connected to special interface (should be autodetected) stretch stretch image to adapt low resolution modes to higer resolutions of flat panel monitors connected to special interface center center image to adapt low resolution modes to higer resolutions of flat panel monitors connected to special interface memsize use if autodetected memsize is wrong ... should never be necessary nopcirr disable PCI read retry nopciwr disable PCI write retry nopcirb disable PCI read bursts nopciwb disable PCI write bursts bpp bpp for specified modes valid values: 8 || 16 || 24 || 32 ref refresh rate for specified mode valid values: 50 <= ref <= 85 mode 640x480 or 800x600 or 1024x768 or 1280x1024 if not specified, the startup mode will be detected and used, so you might also use the vga=??? parameter described in vesafb.txt. If you do not specify a mode, bpp and ref parameters are ignored. verbosity 0 is the default, increase to at least 2 for every bug report! Development hints ================= It's much faster do compile a module and to load the new version after unloading the old module than to compile a new kernel and to reboot. So if you try to work on cyblafb, it might be a good idea to use cyblafb as a module. In real life, fast often means dangerous, and that's also the case here. If you introduce a serious bug when cyblafb is compiled into the kernel, the kernel will lock or oops with a high probability before the file system is mounted, and the danger for your data is low. If you load a broken own version of cyblafb on a running system, the danger for the integrity of the file system is much higher as you might need a hard reset afterwards. Decide yourself. Module unloading, the vfb method ================================ If you want to unload/reload cyblafb using the virtual framebuffer, you need to enable vfb support in the kernel first. After that, load the modules as shown below: modprobe vfb vfb_enable=1 modprobe fbcon modprobe cyblafb fbset -fb /dev/fb1 1280x1024-60 -vyres 2662 con2fb /dev/fb1 /dev/tty1 ... If you now made some changes to cyblafb and want to reload it, you might do it as show below: con2fb /dev/fb0 /dev/tty1 ... rmmod cyblafb modprobe cyblafb con2fb /dev/fb1 /dev/tty1 ... Of course, you might choose another mode, and most certainly you also want to map some other /dev/tty* to the real framebuffer device. You might also choose to compile fbcon as a kernel module or place it permanently in the kernel. I do not know of any way to unload fbcon, and fbcon will prevent the framebuffer device loaded first from unloading. [If there is a way, then please add a description here!] Module unloading, the vesafb method =================================== Configure the kernel: <*> Support for frame buffer devices [*] VESA VGA graphics support <M> Cyberblade/i1 support Add e.g. "video=vesafb:ypan vga=0x307" to the kernel parameters. The ypan parameter is important, choose any vga parameter you like as long as it is a graphics mode. After booting, load cyblafb without any mode and bpp parameter and assign cyblafb to individual ttys using con2fb, e.g.: modprobe cyblafb con2fb /dev/fb1 /dev/tty1 Unloading cyblafb works without problems after you assign vesafb to all ttys again, e.g.: con2fb /dev/fb0 /dev/tty1 rmmod cyblafb