Il sistema è questo ma io nn mi prendo nessuna responsabilita sul uso uso e/o danni che esso possa causare: Use an extended dektop with your iBook Now with OS X support! Please note that I cannot be responsible for any damage that you might do to your computer. This site is for educational purposes only and you are responsible for everything you do with the given information. Ever wondered why your new iBook (16MB VRAM) can't display an extended desktop on an external screen even though it has a Radeon chip that does support this feature? Well, for some reason Apple decided to lock this function. The good news is that I've been working on a solution for some time now. At first I discovered how to enable an extended desktop (also called screen spanning or dual head mode) with a trick in Mac OS 9. This, however, didn't satisfy me and many others for too long because I like to use Mac OS X. So I went at it and found a solution. I assumed that the ATI driver reads the value of a variable defined in the Open Firmware and decides, depending on the value of that variable, whether to limit the external screen to mirroring. The key was to find that variable and to change it to a value that would cause the driver to allow the dual head feature. I was lucky and found the variable and came up with a firmware script that changes this variable every time you turn on your iBook. Since this hack is done in Open Firmware it works with both Mac OS 9 and Mac OS X. I used my iBook with dual displays for a while in OS X and OS 9 and didn't experience any problems. This patch works with current iBooks, which have the ATI Radeon Mobility (sometimes reffered to as RageM6) only. According to the Apple Store these are the model numbers of the supported systmes: M8600*/A, M8602*/A, M8603*/A. Apple System Profiler should give you the following information: From the feedback I received so far I can conclude that the iMac G4 15", the eMac and older iBooks without the Radeon Mobility chip do not support this feature. I doubt that there will be a solution for these systems in the future (please read this page for additional information). Chances for a firmware based solution for the 17" iMac are good. I was able to use an extended desktop in OS 9 already (with the 'old' method of swapping rom files). I hope to present a solution soon. Warning: Don't use this patch with ATI Rage based iBooks! They could possibly die! Since the patch didn't enable dual head mode on any Rage iBook (based on reader feedback) it's not worth to take the risk of possibly damaging your iBook. This accounts to Rage iBooks only. There haven't been significant problems with the Radeon iBooks. The only problems noted for those iBooks were that it simply didn't enable dual head mode but I suspect that the few who reported this did something wrong in applying the patch. Their iBooks were not damaged. Please read this page for additional information. The Patch Since this patch is done in Open Firmware you have to boot your iBook with pressed Command-, Option-, O- and F-keys. At the command line promt you have to enter the lines exactly as they appear in the gray box below (including spaces and quotation marks). means you have to press the space bar. return means you have to press the return or enter key. ctrl-c means you have to press the ctrl- and the c-key. 00000000 are eight zeros, not o's! Caution: The command line doesn't interpret international keyboard layouts. If you use a keyboard version other than english you might have to press other keys to achieve the appropriate character. Please note that you won't get any feedback after you enter the 2nd and 3rd line. The line will just appear cleared. That is normal behavior (it's like a text editor that only displays one line so after a carriage return you will be at the next line which will be empty until you type something). Boot Command + Option + O + F 1 nveditreturn 2 " /" select-devreturn 3 00000000 " graphic-options" get-my-property 2drop !return 4 ctrl-c 5 nvstorereturn 6 setenv use-nvramrc? truereturn 7 reset-allreturn The last command will restart your iBook. In case you want to return to your original configuration all you have to do is reset your nvram. This is usually done by pressing the Command-Option-P-R keys while you turn on your computer until the start sound chimes again. If you need more information on this you can search Apple's KBase (I'll add a direct link later when I have more time). After this patch Quartz Extreme will not be active while using two screens. This is the same problem as with the Powerbook G4 with 16 MB VRAM. You can fix this issue by changing the value of GLCompositorMinimumVRAM in the file System/Library/Frameworks/ApplicationServices.framework /Versions/A/Frameworks /CoreGraphics.framework /Versions /A/Resources /Configuration.plist from 16 to 8. The TV adapter mentioned at this site before (see link below for older version) only works in OS 9 since the PAL/NTSC resolutions are not available in OS X (I hope to fix this soon). If you have any suggestions or additions I would appreciate an email from you:
[email protected] If you tried this with a different version of the iBook or iMac (although it is not reccomended to do so) it would be nice if you would let me know if it worked or not so we can share this information with the Mac community. Click here to view an earlier version of this site with instructions for enabling screen spanning in Mac OS 9 without a firmware tweak. Please note that I cannot be responsible for any damage that you might do to your computer. This site is for educational purposes only and you are responsible for everything you do with the given information. Last updated: 10/27/02 ©2002 macparts.de Thanks to Gerd for the nicer HTML layout!
