Unfortunately, Toshiba changed their driver page and I can't find the correct AMD display driver (this is same as SM Bus?) for my computer. I've tried a few and none of them have worked so I thought I'd ask for help.
Here's the website: http://support.toshiba.com/drivers, and my model # is: Toshiba Satellite L755D-S5204, 64 bit windows 7 is the OS and I have an AMD A6 processor with on-board HD graphics card.
I think it is sort of fixed now, the 4th display driver I tried seems to be working even though there were a bunch of failures when I rebooted my laptop. For now we're good, but don't be surprised if you see me again within a day or two
I have tried about 15 different methods to get the SM Bus Controller installed on my Satellite 855d AND get the CCC working and have finally found a foolproof (so far) method of getting it to work. It's slightly complicated but here are the details (I used this on 2 different models of C855D and it worked for both):
1. run the AMD cleanup utility so that there is no AMD software at all installed on your laptop
2. Install AMD Driver 12-10_vista_win7_win8_64_dd_ccc_whgl_net4 (from AMD's website-look in older drivers)
(you can also find this by looking up AMD catalyst 12.10 10-23-12 (might be 10-22-12). After this driver installs you should have access to the full catalyst control center but your SM Bus Controller will still show up as missing.
3. You then have to install Toshiba's AMD display driver TC50118400d.exe.
After you have installed both of the drivers in that exact order you will no longer show the SM Bus Controller Driver as missing and you will be able to use the CCC to make changes to your computer's display and gaming settings. As far as I can tell this should work with all models of the Toshiba Satellite C855D series.
I hope that this helps some of you out there who have dealt with this same nightmare!!!!