Can I change devices permissions with chmod?

Graphics Problem with Macbook Pro/Ubuntu

• I recently set up my old late-2007 Macbook Pro to dual boot OS X and Ubuntu. I'm very new to Ubuntu, and while mucking around I think I seriously screwed something up with my graphics card. Is there any way to fix it? Despite the problems these older Macbook Pros have with graphics cards, I am almost certain it is not hardware-related. I was able to set up the dual boot system fine and installed rEFIt and Ubuntu 12.10. The dash home screen was not rendering properly in Ubuntu, so I found a recommendation to install nvidia-current drivers (sudo apt-get install nvidia-current) then reconfigure them (sudo dpkg-reconfigure nvidia-current) (from http://blog.projectz.me/2012/10/21/setting-up-ubuntu-12-10-on-a-macbook-pro/). I rebooted and this seemed to work great; the dash rendered fine and I was able to use Ubuntu and OS X perfectly. However, at this point, the trackpad in Ubuntu was a little sticky and unresponsive, so I found a solution (http://askubuntu.com/questions/126526/macbook-pro-touchpad-optimization-12-04-lts) to improve it. I navigated to /etc/X11 and no xorg.conf file was there. So I created one in gedit by copying and pasting the example file from that link. I tried saving this to /etc/X11 but I did not have permission to write to the directory. So I looked up how change the permissions to the directory using chmod. I think this is where I made the biggest mistake. I thought I wanted to allow permission to "everyone" to read/write, so I set permissions to "666" for the directory and everything in the directory. I was then able to copy xorg.conf to the directory. sudo chmod 666 /etc/X11 sudo chmod 666 /etc/X11/* sudo cp xorg.conf /etc/X11/xorg.conf I restarted and after selecting Ubuntu from rEFIt, I was taken to the terminal screen and the Ubuntu desktop never loaded. I realized I screwed something up at this point, so I tried to reverse what I did before: sudo rm /etc/X11/xorg.conf sudo chmod 755 /etc/X11 sudo chmod 755 /etc/X11/* I then rebooted and the Ubuntu desktop loaded fine, including the dash. However, after a few minutes it froze. When I rebooted, the apple screen was covered in a blocky green and pink grid pattern, and rEFIt did not load - it went directly to OS X. This worked for a few minutes, but soon gave a kernel panic. After multiple reboots and kernel panics, I decided I should reformat and start again, and booted from the OS X (10.6) dvd. I wiped the hard drive and reinstalled a fresh copy of OS X. However, while setting up the user settings, I encountered two kernel panics, but eventually got through it. I was also able to complete a software update, then an upgrade to 10.8 and another software update. So currently my OS X software is all up to date. However, I am still getting the green and pink grid when I first boot up, and frequent kernel panics. Most commonly, I will be using OS X fine for ~15 min., then there will be a brief flash, after which the computer is totally unresponsive (however the cursor still moves). The screen will then flicker white every minute or so. At this point I'm forced to do a hard reboot. I've tried resetting the NVRAM, which seems to have no effect. I've tried booting into single-user mode and performing /sbin/fsck -fy. This gives "The volume appears to be OK", while the text turns green and pink and distorted. Unfortunately I don't have the 10.6 Install Disc 2, so I can't run Apple Hardware Test; however, considering the problem seems directly caused by my mucking around with the X11 permissions, I really doubt it is a hardware issue. In my naiveté I thought anything I may have screwed up changing permissions in Ubuntu would at least be reversible by reformatting the drive and reinstalling the OS; however, obviously this is not the case, and I've clearly messed up something deeper. Is there anything I can do at this point? Everything I can find online says you have to replace the logic board with these symptoms, which can't be the case if I've only messed something up on the software-side of things... right? Here are the specs: Macbook Pro 15-inch (late 2007) Processor: 2.2 GHz Intel Core 2 Duo Memory: 2 GB 667 MHz DDR2 SDRAM Graphics: NVIDIA GeForce 8600M GT 128 MB

• Answer:

  The Nvidia chips in these MacBook Pros are basically ticking time bombs due to a manufacturing defect. You didn't screw up your video card by doing what you did. This is a total utter coincidence. There is a very slight chance that using the card with the Nvidia Linux drivers made it run a little hotter, but I wouldn't sweat it. This was going to happen eventually. Pretty much nothing will fix it except a logic board replacement, or reflowing the solder like in your link. Here's another sad coincidence: Apple would have replaced it for you for free http://support.apple.com/kb/TS2377 You could go to an Apple Store and beg for mercy, though.