1. Computers
  2. Display Drivers
  3. Graphics Cards
  4. Memory
  5. Motherboards
  6. Processors
  7. Software
  8. Storage
  9. Operating Systems


Facebook RSS Twitter Twitter Google Plus


Phoronix Test Suite

OpenBenchmarking.org

A Preview Of Kernel-Based Mode-Setting

Michael Larabel

Published on 19 April 2008
Written by Michael Larabel
Page 1 of 4 - 9 Comments

There are many new and innovative features brewing within the X.Org development community right now -- among the many are Gallium3D, the TTM memory manager, and MPX (Multi-Pointer X) -- but one of the features that has risen towards the top of the list and delivers visible benefits to the end-user is kernel-based mode-setting. As implied by its name, kernel mode-setting involves moving the mode-setting code for video adapters from the user-space X server drivers into the Linux kernel. This may seem like an uninteresting topic for end-users, but having the mode-setting done in the kernel allows for a cleaner and richer boot process, improved suspend and resume support, and more reliable VT switching (along with other advantages). Kernel mode-setting isn't yet in the mainline Linux kernel nor is the API for it frozen, but Fedora 9 shipping next month will be the first major distribution carrying this initial support. In this article we're looking more closely at kernel mode-setting with the Intel X.Org driver as well as showing videos of kernel-based mode-setting in action.

There is currently work underway in porting the Radeon driver to do kernel mode-setting (the driver is named radeon_ms), but for Fedora 9 the only X.Org driver with this support is the open-source Intel driver. Support for the kernel mode-setting interaction isn't in the mainline xf86-video-intel driver, but the Fedora 9 Intel driver is based upon the intel-kernelmode branch. The intel-kernelmode branch is in turn based upon the intel-batchbuffer branch. Intel-batchbuffer is also the branch that contains the initial DRI2 support, TTM memory management, Render improvements, and other bleeding-edge advancements. Other drivers will turn to using kernel mode-setting once the API is stabilized and can be found in the mainline Linux kernel. On the Mesa/DRM side is a modesetting-101 branch.

Suspend and resume support is improved with kernel mode-setting as the kernel no longer relies upon external resources for restoring the graphics adapters. With the process now being in-kernel, it's able to restore the mode automatically and more quickly. Likewise, virtual terminal switching is also improved as a result. Kernel mode-setting will also allow for an improved debugging experience, as this will eliminate the "hard hang" and make it possible to display a graphical error message (think the "Blue Screen of Death" for Linux). This technology leads to a flicker-free boot experience by only needing to set the video mode once, instead of turning on and off when starting the boot process (in the case of Fedora, with Red Hat Graphical Boot) and then properly initializing the device when the X server has finally started and loading the GNOME Display Manager. Kernel mode-setting has been one of the items on Keith Packard's (Intel) list of features for a happy Linux desktop.

The kernel mode-setting components ship by default with Fedora 9, but the Intel kernel mode-setting isn't enabled by default. In order to make the switch, i915.modeset=1 must be set as one of the kernel command line arguments through GRUB on boot or modifying /boot/grub/grub.conf. Until kernel mode-setting is used by default, this command is necessary to let the system know to use this method as opposed to mode-setting via the user-space X driver.

<< Previous Page
1
Latest Linux Hardware Reviews
  1. Rosewill RS-MI-01: An Ultra Low-Cost Mini-ITX Chassis
  2. D-Link DCS-2330L HD Wireless Network Camera
  3. Gigabyte AM1M-S2H
  4. AMD's New Athlon/Semprons Give Old Phenom CPUs A Big Run For The Money
Latest Linux Articles
  1. The Performance Of Fedora 20 Updated
  2. Clang Fights GCC On AMD's Athlon AM1 APU With Jaguar Cores
  3. Ubuntu 14.04 LTS vs. Oracle Linux vs. CentOS vs. openSUSE
  4. How Much Video RAM Is Needed For Catalyst R3 Graphics?
Latest Linux News
  1. Red Hat Enterprise Linux 7.0 Is Looking Fantastic
  2. Intel Is Launching An Interesting Bay Trail NUC Next Week
  3. Another X.Org EVoC Proposed For OpenGL 4+ Tests
  4. The Best Features Coming With Qt 5.3
  5. Red Hat's RHEL7 RC ISO Is Now Publicly Available
  6. Nuclear Dawn Seems To Run Fine On AMD Linux
  7. KDE 4.14 Release Schedule Published
  8. GCC 4.9.0 Released, Brings Many Compiler Features
  9. OpenSSL Forked By OpenBSD Into LibreSSL
  10. GNOME Has Big Plans For Its Maps Application
  11. NVIDIA Will Soon Probably Introduce OpenCL 1.2 Linux Support
  12. Google Is Financing A Lot Of Great Open-Source Work This Summer
Latest Forum Discussions
  1. New card. Open source drivers only.
  2. Announcing radeontop, a tool for viewing the GPU usage
  3. The GNOME Foundation Is Running Short On Money
  4. Linux Kernel Developers Fed Up With Ridiculous Bugs In Systemd
  5. The Most Amazing OpenGL Tech Demo In 64kb
  6. Script for Fan Speed Control
  7. Torvalds Is Unconvinced By LTO'ing A Linux Kernel
  8. ReactOS Working On A Community Windows OS