LAPTOP1606 Posted October 28, 2009 Share Posted October 28, 2009 Hi all, Firstly I would like to sorry about my English. I am not native English speak so that why! Secondly I would like to thanks this community for you work and contribution. Why I open this topic? I saw many post about try to use old fashion Intel 855 graphic card with OSx 10.5.x but no post success in doing that with a proper kext. In this post I will not also give you a solution how to fix that - sorry! But we can share information/thoughts/suggest here and hopefully one day one genius could help us! My intend is not going to write a new kext - how ever OSx not support Intel 855 from 10.4.1 - but to find a way around to increase the VRAM in order to run iwork, DVD... My Intel 855 card is only give me 7MB of VRAM - very small when it could give more up to 64MB. Damn! So I study a little bit on Intel 855 card and found one document regarding Graphic and Memory control. I copy the most related part below: (the full document could be find here: http://www.intel.com/assets/pdf/datasheet/252615.pdf) GGC – GMCH Graphics Control Register (Device 0) Address Offset: 52–53h Default Value: 0030h Access: Read/Write Size: 16 bits Bit (15:7) Reserved Bit (6:4) Graphics Mode Select (GMS): This field is used to select the amount of Main system memory that is pre-allocated to support the Internal Graphics Device in VGA (non-linear) and Native (linear) modes. The BIOS ensures that system memory is pre-allocated only when Internal Graphics is enabled. 000 = No system memory pre-allocated. Device #2 (IGD) does not claim VGA cycles (Memory and I/O), and the Sub-Class Code field within Device #2 Function #0 Class Code register is 80. 001 = DVMT (UMA) mode, 1 MB of system memory pre-allocated for frame buffer. 010 = DVMT (UMA) mode, 4 MB of system memory pre-allocated for frame buffer. 011 = DVMT (UMA) mode, 8 MB of system memory pre-allocated for frame buffer. 100 = DVMT (UMA) mode, 16 MB of system memory pre-allocated for frame buffer. 101 = DVMT (UMA) mode, 32 MB of system memory pre-allocated for frame buffer. All other combinations reserved. Bit (3:2) Reserved Bit (1) IGD VGA Disable (IVD): 1 = Disable. Device #2 (IGD) does not claim VGA Memory and I/O Mem cycles, and the Sub-Class Code field within Device #2 Function #0 Class Code register is 80. 0 = Enable. Device #2 (IGD) claims VGA Memory and I/O cycles, the Sub-Class Code within Device #2 Class Code register is 00. Bit (0) Reserved In my case I guess Bit (1) set to 0 and Bit (6:4) set to 011, that why I received 7MB (why it is have 1MB different? I do not know). So if we have any tool to access to right address offset (on BIOS? I think?) and set Bit (6:4) to 101 we will receive pre-allocate memory 32 MB, which is enough to run iWork I think!. I did tried to use HWDirect but to be honest, I do not know where is bit I have to change, I am new in this deeply technic. Could you share some thought and may be a solution how we can manage pre-allocate video memory? I very appreciate, thank you for your time. Link to comment Share on other sites More sharing options...
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