Uvesafb: Difference between revisions

Latest revision as of 15:51, 20 March 2024

This article or section needs language, wiki syntax or style improvements. See Help:Style for reference.

Reason: Many Help:Style issues (Discuss in Talk:Uvesafb)

This article or section needs expansion.

Reason: Since this is the redirect for framebuffer, it should mention what a framebuffer is, what it does, why we care, etc. (Discuss in Talk:Uvesafb)

In contrast with other framebuffer drivers, uvesafb needs a userspace virtualizing daemon, called v86d^AUR. It may seem foolish to emulate x86 code on a x86, but this is important if one wants to use the framebuffer code on other architectures (notably non-x86 ones). It was added in kernel 2.6.24 and has many more features than the standard vesafb, including:

Proper blanking and hardware suspension after delay
Support for custom resolutions as in the system BIOS.

It should support as much hardware as vesafb.

Installation

Install the uvesafb-dkms^AUR package.

Configuration

Remove any framebuffer-related kernel parameter from the boot loader configuration to disable the old vesafb framebuffer from loading. The following commands should return no result:

$ grep vga /proc/cmdline
$ grep -ir vga /etc/modprobe.d/

If you do have a vga= option somewhere, you will need to remove it.

mkinitcpio hook

Add the v86d hook to HOOKS in /etc/mkinitcpio.conf. This allows uvesafb to take over at boot time.

HOOKS=(base udev v86d ...)

Define a resolution

The settings for uvesafb are defined in /usr/lib/modprobe.d/uvesafb.conf.

Documentation for mode_option can be found at [1].

To prevent your customizations being overwritten when the package is updated, copy this file to /etc/modprobe.d/uvesafb.conf:

# cp /usr/lib/modprobe.d/uvesafb.conf /etc/modprobe.d/uvesafb.conf

and then make sure /etc/mkinitcpio.conf includes modconf in the HOOKS array.

To make changes take effect, regenerate the initramfs and reboot the system.

Optimizing resolution

A list of possible resolutions can be generated via the following command:

$ cat /sys/bus/platform/drivers/uvesafb/uvesafb.0/vbe_modes

Users can then modify /usr/lib/modprobe.d/uvesafb.conf with any entry returned above.

Checking current resolution

Either of following commands can be used to show the current framebuffer resolution as a sanity check to see that settings are honored:

$ cat /sys/devices/virtual/graphics/fbcon/subsystem/fb0/virtual_size

$ cat /sys/class/graphics/fb0/virtual_size

Kernel module parameters

If you compile your own kernel then you can also compile uvesafb into the kernel and run v86d later. In this case, the options can be passed as kernel parameters in the format video=uvesafb:options.

Troubleshooting

Uvesafb cannot reserve memory

Check if you forgot to remove any vga= kernel parameter − this overrides the UVESA framebuffer with a standard VESA one.

Try to add video=vesa:off vga=normal to the kernel command line.

@@ Line 1: / Line 1: @@
 [[Category:Graphics]]
 [[Category:Eye candy]]
-[[it:Uvesafb]]
+[[ja:Uvesafb]]
-[[zh-CN:Uvesafb]]
+[[zh-hans:Uvesafb]]
-In contrast with other framebuffer drivers, uvesafb needs a userspace virtualizing daemon, called v86d. It may seem foolish to emulate x86 code on a x86, but this is important if one wants to use the framebuffer code on other architectures (notably non-x86 ones).  A new framebuffer driver has been added to kernel 2.6.24. It has many more features than the standard vesafb, including:
+{{Related articles start}}
+{{Related|Kernel modules}}
+{{Related|Kernel parameters}}
+{{Related|sysctl}}
+{{Related articles end}}
+{{Style|Many [[Help:Style]] issues}}
+{{Expansion|Since this is the redirect for [[framebuffer]], it should mention what a framebuffer is, what it does, why we care, etc.}}
+In contrast with other framebuffer drivers, uvesafb needs a userspace virtualizing daemon, called {{AUR|v86d}}. It may seem foolish to emulate x86 code on a x86, but this is important if one wants to use the framebuffer code on other architectures (notably non-x86 ones).  It was added in kernel 2.6.24 and has many more features than the standard vesafb, including:
 # Proper blanking and hardware suspension after delay
 # Support for custom resolutions as in the system BIOS.
@@ Line 10: / Line 17: @@
 == Installation ==
-[[pacman|Install]] {{aur|v86d}} from [[AUR]].
+[[Install]] the {{aur|uvesafb-dkms}} package.
-== Prepare the system ==
+== Configuration ==
-Remove any framebuffer-related kernel boot parameter from the bootloader configuration to disable the old vesafb framebuffer from loading.
+Remove any framebuffer-related [[kernel parameter]] from the [[boot loader]] configuration to disable the old vesafb framebuffer from loading. The following commands should return no result:
   $ grep vga /proc/cmdline
   $ grep -ir vga /etc/modprobe.d/
-Should return no results. If you do have a {{ic|1=vga=}} option somewhere, you will need to remove it.
+If you do have a {{ic|1=vga=}} option somewhere, you will need to remove it.
-=== GRUB ===
+=== mkinitcpio hook ===
-{{note|This might not work.}}
-First edit {{ic|/etc/default/grub}} commenting the {{ic|1=GRUB_GFXPAYLOAD_LINUX=keep}} line.
-Then regenerate {{ic|grub.cfg}} via the standard script:
+Add the v86d hook to HOOKS in {{ic|/etc/mkinitcpio.conf}}. This allows uvesafb to take over at boot time.
- # grub-mkconfig -o /boot/grub/grub.cfg
-=== GRUB legacy ===
-Remove all references to {{ic|vga<nowiki>=</nowiki>xxx}} from kernel lines in {{ic|/boot/grub/menu.lst}} to allow correct operation of uvesafb.
-=== Systemd ===
-With systemd add the v86d hook to HOOKS in {{ic|/etc/mkinitcpio.conf}}. This allows uvesafb to take over at boot time.
-  HOOKS="base udev v86d ..."
+  HOOKS=(base udev v86d ...)
-== Configure uvesafb ==
 === Define a resolution ===
-The settings for uvesafb are defined in {{ic|/usr/lib/modprobe.d/uvesafb.conf}}:
+The settings for uvesafb are defined in {{ic|/usr/lib/modprobe.d/uvesafb.conf}}.
- # This file sets the parameters for uvesafb module.
- # The following format should be used:
- # options uvesafb mode_option=<xres>x<yres>[-<bpp>][@<refresh>] scroll=<ywrap|ypan|redraw> ...
- #
- # For more details see:
- # http://www.kernel.org/doc/Documentation/fb/uvesafb.txt
- #
- options uvesafb mode_option=1280x800-32 scroll=ywrap
-Documentation for {{ic|mode_option}} can be found at [http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/fb/modedb.txt linux.git/tree/Documentation/fb/modedb.txt]
+Documentation for {{ic|mode_option}} can be found at [https://docs.kernel.org/fb/modedb.html].
 To prevent your customizations being overwritten when the package is updated, copy this file to {{ic|/etc/modprobe.d/uvesafb.conf}}:
@@ Line 60: / Line 44: @@
   # cp /usr/lib/modprobe.d/uvesafb.conf /etc/modprobe.d/uvesafb.conf
-and then add an entry in the FILES section of {{ic|/etc/mkinitcpio.conf}} pointing to your configuration file, like so:
+and then make sure {{ic|/etc/mkinitcpio.conf}} includes {{ic|modconf}} in the {{ic|HOOKS}} array.
- FILES="/etc/modprobe.d/uvesafb.conf"
-To make changes take effect you need to regenerate the ''initramfs'' images of the kernel.
- # mkinitcpio -p linux
-Reboot the system to see the changes take effect.
+To make changes take effect, [[regenerate the initramfs]] and reboot the system.
-=== Optimizing Resolution ===
+=== Optimizing resolution ===
 A list of possible resolutions can be generated via the following command:
@@ Line 78: / Line 56: @@
 Users can then modify {{ic|/usr/lib/modprobe.d/uvesafb.conf}} with any entry returned above.
-=== Checking Current Resolution ===
+=== Checking current resolution ===
 Either of following commands can be used to show the current framebuffer resolution as a sanity check to see that settings are honored:
@@ Line 86: / Line 64: @@
   $ cat /sys/class/graphics/fb0/virtual_size
-== Uvesafb compiled into the kernel ==
+== Kernel module parameters ==
-{{Expansion}}
+If you compile your own kernel then you can also compile uvesafb into the kernel and run v86d later. In this case, the options can be passed as [[kernel parameters]] in the format {{ic|1=video=uvesafb:''options''}}.
-If you compile your own kernel, then you can also compile uvesafb into the kernel and run v86d later, e.g. from {{ic|/etc/rc.local}}. In this case, the options can be passed as kernel boot parameters in the format video=uvesafb:<options>. Please note that this solution is not viable in the case you want to combine uvesafb with 915resolution as suggested below.
-== Uvesafb and 915resolution ==
-In the following, we address a more complex scenario. Many intel video chipsets for widescreen laptops are known to have a buggy BIOS, which does not support the main, native resolution of the wide screen! For this reason, 915resolution was created to patch the BIOS at boot time and allow the X server to use the widescreen resolution.
-Nowadays, the X server is able to do this without the help of 915resolution. However, 915resolution can be combined with uvesafb in order to obtain a widescreen framebuffer, without any need to launch X at all. In this case, we need to load uvesafb after having run 915resolution, so that uvesafb can resort to the proper resolution.
-=== 915resolution-static ===
-In this scenario, 915resolution needs to be compiled statically (since it is going to be in an initramfs, it can not be linked to external libraries). Thus you CAN NOT use the 915resolution package in the [community] repo. Look instead for {{AUR|915resolution-static}} in the AUR. It compiles 915 resolution statically and provides a 915 resolution hook, so you can run 915resolution before loading uvesafb and get the patched resolution. So install 915resolution-static via makepkg and [[pacman]].
-=== The resolution ===
-You need to edit the 915resolution hook in order to define the BIOS mode you want to replace and and the resolution you want to get. You can get information about all the options for 915resolution with:
- $ 915resolution -h
-Edit {{ic|/lib/initcpio/hooks/915resolution}} and modify the options for 915resolution:
- run_hook ()
- {
-    msg -n ":: Patching the VBIOS..."
-    /usr/sbin/915resolution 5c 1280 800
-    msg "done."
- }
-As default 5c is the code of the BIOS mode to replace. You can get a list of the available BIOS video modes with the command {{ic|915resolution -l}}.
-{{Note|You want to choose the code of a mode that you ''DO NOT'' need (neither in the framebuffer nor in X), because 915resolution will replace it with a new user-defined mode. In the above example, {{ic|1280 800}} is the new desired resolution.}}
-=== The Hooks Array ===
-Add the 915resolution hook and, after it, the v86d hook to HOOKS in {{ic|/etc/mkinitcpio.conf}}. Put them before the hooks for the keymap, the resume from suspension and the filesystems.
- HOOKS="base udev 915resolution v86d ..."
-Then you need to regenerate your initramfs with mkinitcpio (adjust the following command to your setup):
- mkinitcpio -p linux
 == Troubleshooting ==
@@ Line 131: / Line 72: @@
 === Uvesafb cannot reserve memory ===
-Check if you forgot to remove any {{Ic|vga<nowiki>=</nowiki>xxx}} kernel parameter -- this overrides the UVESA framebuffer with a standard VESA one.
+Check if you forgot to remove any {{ic|1=vga=}} kernel parameter − this overrides the UVESA framebuffer with a standard VESA one.
-=== Error: "pci_root PNP0A08:00 address space collision + Uvesafb cannot reserve memory" ===
-This occurs on the Acer Aspire One 751h with the 2.6.34-ARCH kernel; whether it also occurs on other systems is unknown. Even without another framebuffer interfering with the uvesafb setup, uvesafb cannot reserve the necessary memory region.
-You can fix this issue by adding the following to the kernel parameters in your bootloader's configuration.
- pci=nocrs
+Try to add {{ic|1=video=vesa:off vga=normal}} to the [[kernel command line]].
 == See also ==
-* [https://www.kernel.org/doc/Documentation/fb/uvesafb.txt Uvesafb Kernel Page]
+* [https://docs.kernel.org/fb/uvesafb.html Uvesafb Kernel Page]
-* [http://dev.gentoo.org/~spock/projects/uvesafb Gentoo's uvesafb Page]
+* [https://web.archive.org/web/20121118062504/http://dev.gentoo.org/~spock/projects/uvesafb/ Gentoos uvesafb Page]
-* [http://infosnews.5cz.de/VESA_BIOS_Extensions.html#VBE_mode_numbers VESA mode numbers]
+* [[wikipedia:VESA_BIOS_Extensions#VBE_mode_numbers|VESA mode numbers]]