On Wed, 08 Oct 2003 19:12:56 +0000, Raymond Jennings wrote: > >I'd like to suggest that you implement device-specific code as a kernel >module. > >Have something like /dev/videocard or /dev/framebuffer, and a kernel module >to control it > >Cause reads and writes to access video memory, and have IOCTL's for >everything else (including sync frequencies, video modes, palettes, >resolutions, hardware cursors, accelerator functions, anything besides video >memory).
The key problem with this is that kernel modules are Linux-specific, and further often need to be kernel-version specific. XFree86 runs quite well in many non-Linux environments today. Further, for reliability reasons, the goal of minimizing kernel code is one that is healthy in ANY environment. Never go to kernel mode if you don't have to. Remember, each transition to kernel mode costs cycles; if I can do the same operations in user mode, performance will be better. >Implementing a kernel module might give access to more resources, like >tighter console control, asynchronous accelerations, No, I don't think any of that is true. >and it would allow >unprivileged SVGAlib programs to run because the kernel module would do the >dirty work, and a process wouldn't need root privileges to access SVGA. For security reasons, wouldn't you want to restrict access to the kernel module to root programs anyway? You don't want arbitrary code accessing your video card and changing the mode. >Also I have Red Hat 7.0 and when I drag a window, it is SLOW. Scrolling >with xpdf is also very slow. Could you somehow accelerate window movement >and scrolling? I see no difference in blitting from an offscreen pixmap to >a window, and blitting the window from the old position to the new one. In >fact, the window movement ought to be FASTER because BOTH "pixmaps" are in >video memory. Depends on your video card. There are certainly acceleration hooks for screen-to-screen blitting, but each driver implements different accelerations. What video card and driver are you using? -- - Tim Roberts, [EMAIL PROTECTED] Providenza & Boekelheide, Inc. _______________________________________________ Devel mailing list [EMAIL PROTECTED] http://XFree86.Org/mailman/listinfo/devel
