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diff --git a/Documentation/fb/uvesafb.txt b/Documentation/fb/uvesafb.txt deleted file mode 100644 index aa924196c366..000000000000 --- a/Documentation/fb/uvesafb.txt +++ /dev/null @@ -1,184 +0,0 @@ - -uvesafb - A Generic Driver for VBE2+ compliant video cards -========================================================== - -1. Requirements ---------------- - -uvesafb should work with any video card that has a Video BIOS compliant -with the VBE 2.0 standard. - -Unlike other drivers, uvesafb makes use of a userspace helper called -v86d. v86d is used to run the x86 Video BIOS code in a simulated and -controlled environment. This allows uvesafb to function on arches other -than x86. Check the v86d documentation for a list of currently supported -arches. - -v86d source code can be downloaded from the following website: - - https://github.com/mjanusz/v86d - -Please refer to the v86d documentation for detailed configuration and -installation instructions. - -Note that the v86d userspace helper has to be available at all times in -order for uvesafb to work properly. If you want to use uvesafb during -early boot, you will have to include v86d into an initramfs image, and -either compile it into the kernel or use it as an initrd. - -2. Caveats and limitations --------------------------- - -uvesafb is a _generic_ driver which supports a wide variety of video -cards, but which is ultimately limited by the Video BIOS interface. -The most important limitations are: - -- Lack of any type of acceleration. -- A strict and limited set of supported video modes. Often the native - or most optimal resolution/refresh rate for your setup will not work - with uvesafb, simply because the Video BIOS doesn't support the - video mode you want to use. This can be especially painful with - widescreen panels, where native video modes don't have the 4:3 aspect - ratio, which is what most BIOS-es are limited to. -- Adjusting the refresh rate is only possible with a VBE 3.0 compliant - Video BIOS. Note that many nVidia Video BIOS-es claim to be VBE 3.0 - compliant, while they simply ignore any refresh rate settings. - -3. Configuration ----------------- - -uvesafb can be compiled either as a module, or directly into the kernel. -In both cases it supports the same set of configuration options, which -are either given on the kernel command line or as module parameters, e.g.: - - video=uvesafb:1024x768-32,mtrr:3,ywrap (compiled into the kernel) - - # modprobe uvesafb mode_option=1024x768-32 mtrr=3 scroll=ywrap (module) - -Accepted options: - -ypan Enable display panning using the VESA protected mode - interface. The visible screen is just a window of the - video memory, console scrolling is done by changing the - start of the window. This option is available on x86 - only and is the default option on that architecture. - -ywrap Same as ypan, but assumes your gfx board can wrap-around - the video memory (i.e. starts reading from top if it - reaches the end of video memory). Faster than ypan. - Available on x86 only. - -redraw Scroll by redrawing the affected part of the screen, this - is the default on non-x86. - -(If you're using uvesafb as a module, the above three options are - used a parameter of the scroll option, e.g. scroll=ypan.) - -vgapal Use the standard VGA registers for palette changes. - -pmipal Use the protected mode interface for palette changes. - This is the default if the protected mode interface is - available. Available on x86 only. - -mtrr:n Setup memory type range registers for the framebuffer - where n: - 0 - disabled (equivalent to nomtrr) - 3 - write-combining (default) - - Values other than 0 and 3 will result in a warning and will be - treated just like 3. - -nomtrr Do not use memory type range registers. - -vremap:n - Remap 'n' MiB of video RAM. If 0 or not specified, remap memory - according to video mode. - -vtotal:n - If the video BIOS of your card incorrectly determines the total - amount of video RAM, use this option to override the BIOS (in MiB). - -<mode> The mode you want to set, in the standard modedb format. Refer to - modedb.txt for a detailed description. When uvesafb is compiled as - a module, the mode string should be provided as a value of the - 'mode_option' option. - -vbemode:x - Force the use of VBE mode x. The mode will only be set if it's - found in the VBE-provided list of supported modes. - NOTE: The mode number 'x' should be specified in VESA mode number - notation, not the Linux kernel one (eg. 257 instead of 769). - HINT: If you use this option because normal <mode> parameter does - not work for you and you use a X server, you'll probably want to - set the 'nocrtc' option to ensure that the video mode is properly - restored after console <-> X switches. - -nocrtc Do not use CRTC timings while setting the video mode. This option - has any effect only if the Video BIOS is VBE 3.0 compliant. Use it - if you have problems with modes set the standard way. Note that - using this option implies that any refresh rate adjustments will - be ignored and the refresh rate will stay at your BIOS default (60 Hz). - -noedid Do not try to fetch and use EDID-provided modes. - -noblank Disable hardware blanking. - -v86d:path - Set path to the v86d executable. This option is only available as - a module parameter, and not as a part of the video= string. If you - need to use it and have uvesafb built into the kernel, use - uvesafb.v86d="path". - -Additionally, the following parameters may be provided. They all override the -EDID-provided values and BIOS defaults. Refer to your monitor's specs to get -the correct values for maxhf, maxvf and maxclk for your hardware. - -maxhf:n Maximum horizontal frequency (in kHz). -maxvf:n Maximum vertical frequency (in Hz). -maxclk:n Maximum pixel clock (in MHz). - -4. The sysfs interface ----------------------- - -uvesafb provides several sysfs nodes for configurable parameters and -additional information. - -Driver attributes: - -/sys/bus/platform/drivers/uvesafb - - v86d (default: /sbin/v86d) - Path to the v86d executable. v86d is started by uvesafb - if an instance of the daemon isn't already running. - -Device attributes: - -/sys/bus/platform/drivers/uvesafb/uvesafb.0 - - nocrtc - Use the default refresh rate (60 Hz) if set to 1. - - - oem_product_name - - oem_product_rev - - oem_string - - oem_vendor - Information about the card and its maker. - - - vbe_modes - A list of video modes supported by the Video BIOS along with their - VBE mode numbers in hex. - - - vbe_version - A BCD value indicating the implemented VBE standard. - -5. Miscellaneous ----------------- - -Uvesafb will set a video mode with the default refresh rate and timings -from the Video BIOS if you set pixclock to 0 in fb_var_screeninfo. - - --- - Michal Januszewski <spock@gentoo.org> - Last updated: 2017-10-10 - - Documentation of the uvesafb options is loosely based on vesafb.txt. - |