0 Replies Latest reply on May 3, 2014 2:04 PM by rjsmith92

    How the Video BIOS works in Windows?

    rjsmith92

      Hello All, bit of a random question that I've been struggling to find the answer to online and was wondering if any of you could help.

       

      I was looking at the hardware resources assigned to my graphics card (HD 5850) in device manager and noticed the memory address range usually mapped for the video ROM (C0000h - C7FFFh) was not assigned to the card.

      I looked into it using PCIScope and found that the ROM had been disabled. I know the video BIOS isn't used any more as it runs in a 16 bit environment and drivers are used to access the hardware. What about when Windows is running in an SVGA mode using VESA BIOS Extensions (VBE), for example when displaying the splash screen or if a display driver can't be loaded. Doesn't Windows need to use the Video BIOS for this?

      I disabled my AMD graphics adapter so that Windows was using the VGASAVE driver and the ROM was still disabled, I'm just wondering how this works?

      So basically my questions are does Windows disable the video BIOS and if so how does Windows use the graphics card and VBEs in SVGA modes without being able to use the video BIOS?

      Any help would be appreciated,

      Thanks.