Ubuntu
linux package

  1. Bug #95444
  2. Comment #39

Comment 39 for bug 95444

Revision history for this message
mikes (mikevas) wrote : Re: No Screen Backlight Control; Sony Vaio with nvidia 8 series graphics

I had some progress here. I attached Vista to WinDbg and traced inside the kernel and drivers. I found what it does to change the backlight, but I need some more work in order to port this to Linux. The actual change happens with a call to WRITE_REGISTER_ULONG in a kernel virtual address (9XXXXXXX) with values from 800000f0 (low) to 80000401(full). It seems prety straighforward. There is no port IO as in the pommed driver, and I dont know how this address (9XXXXXXX) is translated to nvidia register addresses and/or physical bus addresses. There are calls to HalTranslateBusAddress and mmMapIoSpace at the initialization of the driver, I'll have to trace those and see where they map the used address spaces. I will work some more on it and post the results.

If anyone is experienced with memory mapped I/O stuff in both Win and Linux, please help!