1CyBlaFB is a framebuffer driver for the Cyberblade/i1 graphics core integrated 2into the VIA Apollo PLE133 (aka vt8601) south bridge. It is developed and 3tested using a VIA EPIA 5000 board. 4 5Cyblafb - compiled into the kernel or as a module? 6================================================== 7 8You might compile cyblafb either as a module or compile it permanently into the 9kernel. 10 11Unless you have a real reason to do so you should not compile both vesafb and 12cyblafb permanently into the kernel. It's possible and it helps during the 13developement cycle, but it's useless and will at least block some otherwise 14usefull memory for ordinary users. 15 16Selecting Modes 17=============== 18 19 Startup Mode 20 ============ 21 22 First of all, you might use the "vga=???" boot parameter as it is 23 documented in vesafb.txt and svga.txt. Cyblafb will detect the video 24 mode selected and will use the geometry and timings found by 25 inspecting the hardware registers. 26 27 video=cyblafb vga=0x317 28 29 Alternatively you might use a combination of the mode, ref and bpp 30 parameters. If you compiled the driver into the kernel, add something 31 like this to the kernel command line: 32 33 video=cyblafb:1280x1024,bpp=16,ref=50 ... 34 35 If you compiled the driver as a module, the same mode would be 36 selected by the following command: 37 38 modprobe cyblafb mode=1280x1024 bpp=16 ref=50 ... 39 40 None of the modes possible to select as startup modes are affected by 41 the problems described at the end of the next subsection. 42 43 For all startup modes cyblafb chooses a virtual x resolution of 2048, 44 the only exception is mode 1280x1024 in combination with 32 bpp. This 45 allows ywrap scrolling for all those modes if rotation is 0 or 2, and 46 also fast scrolling if rotation is 1 or 3. The default virtual y reso- 47 lution is 4096 for bpp == 8, 2048 for bpp==16 and 1024 for bpp == 32, 48 again with the only exception of 1280x1024 at 32 bpp. 49 50 Please do set your video memory size to 8 Mb in the Bios setup. Other 51 values will work, but performace is decreased for a lot of modes. 52 53 Mode changes using fbset 54 ======================== 55 56 You might use fbset to change the video mode, see "man fbset". Cyblafb 57 generally does assume that you know what you are doing. But it does 58 some checks, especially those that are needed to prevent you from 59 damaging your hardware. 60 61 - only 8, 16, 24 and 32 bpp video modes are accepted 62 - interlaced video modes are not accepted 63 - double scan video modes are not accepted 64 - if a flat panel is found, cyblafb does not allow you 65 to program a resolution higher than the physical 66 resolution of the flat panel monitor 67 - cyblafb does not allow vclk to exceed 230 MHz. As 32 bpp 68 and (currently) 24 bit modes use a doubled vclk internally, 69 the dotclock limit as seen by fbset is 115 MHz for those 70 modes and 230 MHz for 8 and 16 bpp modes. 71 - cyblafb will allow you to select very high resolutions as 72 long as the hardware can be programmed to these modes. The 73 documented limit 1600x1200 is not enforced, but don't expect 74 perfect signal quality. 75 76 Any request that violates the rules given above will be either changed 77 to something the hardware supports or an error value will be returned. 78 79 If you program a virtual y resolution higher than the hardware limit, 80 cyblafb will silently decrease that value to the highest possible 81 value. The same is true for a virtual x resolution that is not 82 supported by the hardware. Cyblafb tries to adapt vyres first because 83 vxres decides if ywrap scrolling is possible or not. 84 85 Attempts to disable acceleration are ignored, I believe that this is 86 safe. 87 88 Some video modes that should work do not work as expected. If you use 89 the standard fb.modes, fbset 640x480-60 will program that mode, but 90 you will see a vertical area, about two characters wide, with only 91 much darker characters than the other characters on the screen. 92 Cyblafb does allow that mode to be set, as it does not violate the 93 official specifications. It would need a lot of code to reliably sort 94 out all invalid modes, playing around with the margin values will 95 give a valid mode quickly. And if cyblafb would detect such an invalid 96 mode, should it silently alter the requested values or should it 97 report an error? Both options have some pros and cons. As stated 98 above, none of the startup modes are affected, and if you set 99 verbosity to 1 or higher, cyblafb will print the fbset command that 100 would be needed to program that mode using fbset. 101 102 103Other Parameters 104================ 105 106 107crt don't autodetect, assume monitor connected to 108 standard VGA connector 109 110fp don't autodetect, assume flat panel display 111 connected to flat panel monitor interface 112 113nativex inform driver about native x resolution of 114 flat panel monitor connected to special 115 interface (should be autodetected) 116 117stretch stretch image to adapt low resolution modes to 118 higer resolutions of flat panel monitors 119 connected to special interface 120 121center center image to adapt low resolution modes to 122 higer resolutions of flat panel monitors 123 connected to special interface 124 125memsize use if autodetected memsize is wrong ... 126 should never be necessary 127 128nopcirr disable PCI read retry 129nopciwr disable PCI write retry 130nopcirb disable PCI read bursts 131nopciwb disable PCI write bursts 132 133bpp bpp for specified modes 134 valid values: 8 || 16 || 24 || 32 135 136ref refresh rate for specified mode 137 valid values: 50 <= ref <= 85 138 139mode 640x480 or 800x600 or 1024x768 or 1280x1024 140 if not specified, the startup mode will be detected 141 and used, so you might also use the vga=??? parameter 142 described in vesafb.txt. If you do not specify a mode, 143 bpp and ref parameters are ignored. 144 145verbosity 0 is the default, increase to at least 2 for every 146 bug report! 147 148Development hints 149================= 150 151It's much faster do compile a module and to load the new version after 152unloading the old module than to compile a new kernel and to reboot. So if you 153try to work on cyblafb, it might be a good idea to use cyblafb as a module. 154In real life, fast often means dangerous, and that's also the case here. If 155you introduce a serious bug when cyblafb is compiled into the kernel, the 156kernel will lock or oops with a high probability before the file system is 157mounted, and the danger for your data is low. If you load a broken own version 158of cyblafb on a running system, the danger for the integrity of the file 159system is much higher as you might need a hard reset afterwards. Decide 160yourself. 161 162Module unloading, the vfb method 163================================ 164 165If you want to unload/reload cyblafb using the virtual framebuffer, you need 166to enable vfb support in the kernel first. After that, load the modules as 167shown below: 168 169 modprobe vfb vfb_enable=1 170 modprobe fbcon 171 modprobe cyblafb 172 fbset -fb /dev/fb1 1280x1024-60 -vyres 2662 173 con2fb /dev/fb1 /dev/tty1 174 ... 175 176If you now made some changes to cyblafb and want to reload it, you might do it 177as show below: 178 179 con2fb /dev/fb0 /dev/tty1 180 ... 181 rmmod cyblafb 182 modprobe cyblafb 183 con2fb /dev/fb1 /dev/tty1 184 ... 185 186Of course, you might choose another mode, and most certainly you also want to 187map some other /dev/tty* to the real framebuffer device. You might also choose 188to compile fbcon as a kernel module or place it permanently in the kernel. 189 190I do not know of any way to unload fbcon, and fbcon will prevent the 191framebuffer device loaded first from unloading. [If there is a way, then 192please add a description here!] 193 194Module unloading, the vesafb method 195=================================== 196 197Configure the kernel: 198 199 <*> Support for frame buffer devices 200 [*] VESA VGA graphics support 201 <M> Cyberblade/i1 support 202 203Add e.g. "video=vesafb:ypan vga=0x307" to the kernel parameters. The ypan 204parameter is important, choose any vga parameter you like as long as it is 205a graphics mode. 206 207After booting, load cyblafb without any mode and bpp parameter and assign 208cyblafb to individual ttys using con2fb, e.g.: 209 210 modprobe cyblafb 211 con2fb /dev/fb1 /dev/tty1 212 213Unloading cyblafb works without problems after you assign vesafb to all 214ttys again, e.g.: 215 216 con2fb /dev/fb0 /dev/tty1 217 rmmod cyblafb 218