QEMU VBE linear frame buffer(solved)
Posted: Sun Oct 26, 2008 11:12 am
I am currently doing some graphics support stuff in my OS. I have a vbe driver which registers and allows me to use both bank switched and linear frame buffer modes.
In order to find whether a mode supports lfb i check its mode attributes. If it does I check if the lfb mode is supported by passing the mode number ORred with 0x4000 to the get mode info function.
My first question is, is this right (passing the 0x4000 ORred mode to check for lfb) ?
This call though, is successful and I set the mode. This works both in Bochs (which supports LFB) and MS virtual pc 2007 (which does not, and hence my driver is able to detect it, and automatically use bank switched mode).
But in QEMU (VBE v2.0) , i find that it does support LFB but when I set the mode, I cannot draw to the mode, even if it is direct color and 24 bpp which is native to my os.
Is this a bug?
In order to find whether a mode supports lfb i check its mode attributes. If it does I check if the lfb mode is supported by passing the mode number ORred with 0x4000 to the get mode info function.
My first question is, is this right (passing the 0x4000 ORred mode to check for lfb) ?
This call though, is successful and I set the mode. This works both in Bochs (which supports LFB) and MS virtual pc 2007 (which does not, and hence my driver is able to detect it, and automatically use bank switched mode).
But in QEMU (VBE v2.0) , i find that it does support LFB but when I set the mode, I cannot draw to the mode, even if it is direct color and 24 bpp which is native to my os.
Is this a bug?