CompuServe Thread

ATI Mach64 & Vibrant

1 messages in this thread
#121325From: Aug 31, 1994 11:06 AM
The following is a message from Tim Little about the ATI Mach 64 delay problems. ____________________________________________________________________________ I am the engineer responsible for the ATI driver from Vibrant Graphics which is generating all of the conversation. Here are the details in no ambiguous terms, I have looked through the code and KNOW what it is doing. 1). What Gus has said about the VESA calls seems to be true, if we don't make the call into ATI's bios to querry the board information, the initialization time drops dramaticaly. We must make this call in order to not destablize the product. 2). There are a number of reasons the call must be made. a). We need to be able to detect if we are on an ISA version of the card, because with the ISA version you cannot make the linear frame buffer accesses. b). If we don't make the call, we cannot check to see if the mode you selected is supported by the ATI in it's current configuration. ATI goes to a lot of trouble to protect the user from damaging his/her monitor by initializing a mode which is not supported, without this call, we are not using ATI's standard conventions for mode initialization. c). We use the call to get the amount of memory that is available on the card so we can make effective use of the offscreen memory and speed up many of the operations that are done in 3DS. 3). I am attempting to work with ATI on a resolusion to this problem. It is not as trivial as it might seem, to get a resolution which does not destablize the driver but provides the performance which everyone has every right to expect. PS: The call in question takes aproximately 5sec to to return on a p-66. And it must be made every time the mode changes. At startup in 3DS, all modes are initialized to make sure that you have a valid configuration before letting you get started on changes only to have to leave 3DS and change your config. Tim Little — Vibrant Graphics Inc. tim@vibrant.com