Xfree86 drivers versus kernel drivers
Hi, I am having some difficulty understanding the fundamental differences between xfree86 drivers and linux kernel drivers. Is there a good reference somewhere? I have read that xfree86 drivers are really user space programs that map the graphic video memory and then access it. If so does xfree86 needs anything at all from the linux kernel stuff that is in ./drivers/video ? Or is that stuff just needed by linux so that it can print out boot messages before X starts? Thanks a lot, -jf simon ___ Découvrez un nouveau moyen de poser toutes vos questions quelque soit le sujet ! Yahoo! Questions/Réponses pour partager vos connaissances, vos opinions et vos expériences. http://fr.answers.yahoo.com ___ Devel mailing list Devel@XFree86.Org http://XFree86.Org/mailman/listinfo/devel
Re: Xfree86 drivers versus kernel drivers
jf simon wrote: I am having some difficulty understanding the fundamental differences between xfree86 drivers and linux kernel drivers. Is there a good reference somewhere? I'm not sure a reference is really necessary. The only problem is that the word driver is overloaded. XFree86 drivers and kernel drivers are both dynamically loadable modules, like a Linux shared object or a Windows DLL. XFree86 happens to have its own module loader, so that a single XFree86 driver binary can be loaded regardless of operating system. Kernel drivers are loaded into the kernel, and run in the privileged kernel mode. XFree86 drivers are loaded by the XFree86 server process. It is a user-mode process, although it must run as root in order to touch I/O ports. Historically, the original Windows NT 3.x had the exact same design. Display drivers were actually user-mode DLLs that ran in a separate process (called CSRSS). Users complained about the task-switch overhead, and so Microsoft moved display drivers into the kernel in NT 4. It's still not clear this was a net win. I have read that xfree86 drivers are really user space programs that map the graphic video memory and then access it. Basically correct, although XFree86 drivers are not really programs. They are just modules that are loaded by the XFree86 server program. If so does xfree86 needs anything at all from the linux kernel stuff that is in ./drivers/video ? Or is that stuff just needed by linux so that it can print out boot messages before X starts? Remember that XFree86 is not a fundamental part of Linux. It's just another Linux application. Linux runs perfectly well without XFree86, and the kernel video stuff supports that. Most XFree86 drivers use the Linux kernel video stuff only for mapping the frame buffer into memory (via the mmap system call). Some drivers use more than that. If a graphics chip requires the use of DMA, as some do, then the XFree86 driver has to rely on a kernel component for help. Almost all of the OpenGL drivers need a kernel component for that reason. -- Tim Roberts, [EMAIL PROTECTED] Providenza Boekelheide, Inc. ___ Devel mailing list Devel@XFree86.Org http://XFree86.Org/mailman/listinfo/devel
Re: Xfree86 drivers versus kernel drivers
* Tim Roberts [EMAIL PROTECTED] wrote: Hi folks, Kernel drivers are loaded into the kernel, and run in the privileged kernel mode. To be a hair-splitting, not completely correct: kernel drivers (at least on GNU/Linux) can be either built into the kernel *or* loaded dynamically. On certain platforms, buitin drivers *may* be slightly more efficient (near jumps possible, etc) But from the user's view, the difference is quite irrelevant ;-) The communication between userland and kernel drivers mostly happens through device files - that's the unix philosophy: evrything's a file :) Userland drivers are simply called like just any other library. XFree86 drivers are loaded by the XFree86 server process. But they may also sit on top of kernel drivers. For example several mouse drivers actually call the certain kernel drivers to most of the work (aka reading data from the serial interface). Another example is the DRI stuff, which does much of the (critical) rendering work in kernelspace. Historically, the original Windows NT 3.x had the exact same design. Display drivers were actually user-mode DLLs that ran in a separate process (called CSRSS). Users complained about the task-switch overhead, and so Microsoft moved display drivers into the kernel in NT 4. It's still not clear this was a net win. As far as I remember, the NT model was much more low-level than X11, so the percentage of data to pass through processes vs. data rendered within the display server was much worse than on X11. But I'm not an NT expert ... Today, X11 has several extensions for speeding up certain load intesive screen operations, ie. playing videos locally. BTW: could anyone point out if there are major differences between traditional xf86 and current Xorg ? snip If so does xfree86 needs anything at all from the linux kernel stuff that is in ./drivers/video ? Or is that stuff just needed by linux so that it can print out boot messages before X starts? Remember that XFree86 is not a fundamental part of Linux. It's just another Linux application. In fact, xf86/xorg runs on many platforms. Historically, xf86 was an fork of old xorg, optimized for x86 platforms. While xorg development was stalled for quite a long time, xf86 brought many improvements which now went into new xorg. snip Linux runs perfectly well without XFree86, and the kernel video stuff supports that. Most XFree86 drivers use the Linux kernel video stuff only for mapping the frame buffer into memory (via the mmap system call). The Linux video drivers are their own layer. They provide lots of low-level things, ie. device independent framebuffers access and some rendering primitives. xf86/xorg - when running on GNU/Linux - sits on top of it. And there's another interesting layer: DirectFB. It's an platform intependent framebuffer access library (living in userland), and there's an Xserver which sits on top of it. So the Xserver actually has no more device drivers, but instead lets DirectFB does all this work. cu -- - Enrico Weigelt== metux IT service - http://www.metux.de/ - Please visit the OpenSource QM Taskforce: http://wiki.metux.de/public/OpenSource_QM_Taskforce Patches / Fixes for a lot dozens of packages in dozens of versions: http://patches.metux.de/ - ___ Devel mailing list Devel@XFree86.Org http://XFree86.Org/mailman/listinfo/devel
Re: Xfree86 drivers versus kernel drivers
Enrico Weigelt wrote: * Tim Roberts [EMAIL PROTECTED] wrote: Historically, the original Windows NT 3.x had the exact same design. Display drivers were actually user-mode DLLs that ran in a separate process (called CSRSS). Users complained about the task-switch overhead, and so Microsoft moved display drivers into the kernel in NT 4. It's still not clear this was a net win. As far as I remember, the NT model was much more low-level than X11, so the percentage of data to pass through processes vs. data rendered within the display server was much worse than on X11. But I'm not an NT expert ... We're getting a bit far afield here, but I'm always willing to orate at length on arcane topics of little interest to anyone. The XFree86 approach is not all that different from the old NT approach. The Xlib application interface is similar to the GDI application interface. The XAA driver interface is similar in many ways to the GDI driver interface. The major difference is that, whereas X crosses that gap by feeding X protocol through a socket (thereby enabling client and server on different machines), NT crossed that gap by using an RPC mechanism. BTW: could anyone point out if there are major differences between traditional xf86 and current Xorg ? In practical terms, there are no major differences. X.org branched from XFree86 at version 4.3.99, so at that point, they were identical. I would judge that there has been more activity on the source base since then by X.org, but I may be out of touch. The Linux video drivers are their own layer. They provide lots of low-level things, ie. device independent framebuffers access and some rendering primitives. xf86/xorg - when running on GNU/Linux - sits on top of it. Only in a fleeting way. As I said, most 2D XFree86 drivers use the kernel video drivers to map the frame buffer into memory, and nothing else. Last time I looked, the kernel video drivers did not expose any graphics accelerator features at all, making them useless to XFree86. -- Tim Roberts, [EMAIL PROTECTED] Providenza Boekelheide, Inc.
[XFree86] xfree86 emulation of VGA BIOS cards on powerpc platforms
Hi, For non x86 architecture like PowerPC, I understand that xfree86 is able to initialize PCI graphic cards, by emulating the VGA BIOS extension located on the graphic card. We are using IBM Maple platform (featuring a IBM 970 ppc64 processor). When we boot linux, nothing happens as it seems the graphic card used (ATI Radeon 7000) is not initialized. Does emulation for powerPC works in xfree86? Thanks -jf simon ___ Découvrez un nouveau moyen de poser toutes vos questions quelque soit le sujet ! Yahoo! Questions/Réponses pour partager vos connaissances, vos opinions et vos expériences. http://fr.answers.yahoo.com ___ XFree86 mailing list XFree86@XFree86.Org http://XFree86.Org/mailman/listinfo/xfree86
[XFree86] 4.6.0 breaks XDM
Hello, First of all, I'm still fairly new to XFree86 (and indeed X11 in general) but am learning. I have Linux 2.6 with an Intel 82810 DC100 and a Compaq Presario MV500 Color Monitor. It was working fine while I had a Samsung SyncMaster 700IFT hooked up to it, and XFree86 4.3.9, but I moved the computer into a different place and this was the monitor I got. I had to reconfigure the monitor. I screwed up my keyboard configuration (every key I pressed changed the resolution) while messing around with the monitor, so I decided alright, time to upgrade. I downloaded XFree86 4.6.0 from the FTP, got all the necessary tgzs in hand, and installed. It finished, and at first glance it worked! I startxed and got xterm. I pushed a key and it put it on the display. Yay! Now, I have a new problem. I can't graphically login, or use XFree86 at all, anymore. I type my name and password, it flashes a black screen, and comes up the login screen, then I type my name and password, well, you get the picture. My /var/log/messages is full of these errors: Aug 9 01:09:51 Linux kdm: :0[5469]: Can't execute /etc/X11/xdm/Xstartup: No such file or directory Aug 9 01:09:51 Linux kdm: :0[4868]: Cannot execute startup script /etc/X11/xdm/Xstartup Aug 9 01:09:51 Linux kdm: :0[5486]: Can't execute /etc/X11/xdm/Xsetup: No such file or directory I unzipped the Xstartup, Xsetup, Xsession, and Xreset files, but then I just got xterm no matter what I tried. I gzip'ed them back up and attempted to copy my old files (from 4.3.9). It flashed a black screen and came up the login screen again when I tried that. So I removed those and now I'm back at square one. Trying to startkde manually came up a bunch of Xlib: connection to ':0.0' refused by server messages (probably because kdm has the server locked). I'm attaching my XF86Config file, the XFree86.0.log file, and screen output of XFree86 -version and uname -a. Thank you for the help! Andrew Wilcox Linux:~ # ./version.sh /media/floppy/Versions XFree86 Version 4.6.0 Release Date: 10 May 2006 X Protocol Version 11, Revision 0 Build Operating System: Linux 2.4.24 i686 [ELF] Current Operating System: Linux Linux 2.6.5-7.111-default #1 Wed Oct 13 15:45:13 UTC 2004 i686 Build Date: 8 May 2006 Changelog Date: 10 May 2006 Before reporting problems, check http://www.XFree86.Org/ to make sure that you have the latest version. Module Loader present Command line: XFree86 -version Linux Linux 2.6.5-7.111-default #1 Wed Oct 13 15:45:13 UTC 2004 i686 i686 i386 GNU/Linux Linux:~ # # /.../ # SaX generated XFree86 config file # Created on: 2006-08-09T00:18:43-0400. # # Version: 4.8 # Contact: Marcus Schaefer [EMAIL PROTECTED], 2002 # # Automatically generated by [ISaX] (4.8) # PLEASE DO NOT EDIT THIS FILE! # Section Files FontPath /usr/X11R6/lib/X11/fonts/misc:unscaled FontPath /usr/X11R6/lib/X11/fonts/local FontPath /usr/X11R6/lib/X11/fonts/75dpi:unscaled FontPath /usr/X11R6/lib/X11/fonts/100dpi:unscaled FontPath /usr/X11R6/lib/X11/fonts/Type1 FontPath /usr/X11R6/lib/X11/fonts/URW FontPath /usr/X11R6/lib/X11/fonts/Speedo FontPath /usr/X11R6/lib/X11/fonts/PEX FontPath /usr/X11R6/lib/X11/fonts/cyrillic FontPath /usr/X11R6/lib/X11/fonts/latin2/misc:unscaled FontPath /usr/X11R6/lib/X11/fonts/latin2/75dpi:unscaled FontPath /usr/X11R6/lib/X11/fonts/latin2/100dpi:unscaled FontPath /usr/X11R6/lib/X11/fonts/latin2/Type1 FontPath /usr/X11R6/lib/X11/fonts/latin7/75dpi:unscaled FontPath /usr/X11R6/lib/X11/fonts/baekmuk:unscaled FontPath /usr/X11R6/lib/X11/fonts/japanese:unscaled FontPath /usr/X11R6/lib/X11/fonts/kwintv FontPath /usr/X11R6/lib/X11/fonts/truetype FontPath /usr/X11R6/lib/X11/fonts/uni:unscaled FontPath /usr/X11R6/lib/X11/fonts/CID FontPath /usr/X11R6/lib/X11/fonts/ucs/misc:unscaled FontPath /usr/X11R6/lib/X11/fonts/ucs/75dpi:unscaled FontPath /usr/X11R6/lib/X11/fonts/ucs/100dpi:unscaled FontPath /usr/X11R6/lib/X11/fonts/hellas/misc:unscaled FontPath /usr/X11R6/lib/X11/fonts/hellas/75dpi:unscaled FontPath /usr/X11R6/lib/X11/fonts/hellas/100dpi:unscaled FontPath /usr/X11R6/lib/X11/fonts/hellas/Type1 FontPath /usr/X11R6/lib/X11/fonts/misc/sgi:unscaled FontPath /usr/X11R6/lib/X11/fonts/xtest FontPath /opt/kde3/share/fonts InputDevices /dev/ttyS0 InputDevices /dev/ttyS1 InputDevices /dev/ttyS2 InputDevices /dev/ttyS3 InputDevices /dev/ttyS4 InputDevices /dev/ttyS5 InputDevices /dev/ttyS6 InputDevices /dev/ttyS7 InputDevices /dev/ttyS8 InputDevices /dev/psaux InputDevices /dev/logibm InputDevices /dev/sunmouse InputDevices /dev/atibm InputDevices /dev/amigamouse InputDevices /dev/atarimouse InputDevices /dev/inportbm InputDevices /dev/gpmdata InputDevices /dev/mouse InputDevices /dev/usbmouse InputDevices /dev/adbmouse
