diff options
Diffstat (limited to 'Documentation/fb/cyblafb/usage')
| -rw-r--r-- | Documentation/fb/cyblafb/usage | 217 |
1 files changed, 0 insertions, 217 deletions
diff --git a/Documentation/fb/cyblafb/usage b/Documentation/fb/cyblafb/usage deleted file mode 100644 index a39bb3d..0000000 --- a/Documentation/fb/cyblafb/usage +++ /dev/null @@ -1,217 +0,0 @@ -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 |
