Fedora9：Linux首次拥有基于Kernel的配置模式（Modesetting）

当Fedora 9在下个月正式发布时，第一次有 Linux发行版提供了基于内核的设置模式，这应该是终端用户特别需要关注的功能。基于Kernel的配置模式提供了一个flicker-free的启动进程，一个更快和更可靠的VT switching ，一个Linux BSOD，以及最让人感兴趣的有很多改进的暂停/重启支持。将配置模式代码从X.Org视频驱动移至Linux kernel并不是很容易，但预计Linux 2.6.27 kernel将正式支持它，而Intel 视频驱动已经可以使用这项技术。 Phoronix 预先检验了这一基于Kernel的配置模式，并用视频展示了虚拟终端配置的大幅度改进。

Phoronix 预先检验了这一基于Kernel的配置模式:

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.