jeffz@sun.com (Jeffrey Zank - SBus Software) (06/01/90)
| What are the implications, if any, of these comments for a DMA driver | running on a Sun4/260 under SunOS4.1? Is there now a general way around | the 600K DVMA limit, i.e. does bp_mapin() on the 4/260 work as described | for the SS1? If you are using DVMA any Sun architechure you will be limited to transfer sizes less than the total DVMA resoruce map size (1MB on non the 4/260 me thinks). If you use bp_mapin() you should be able to get your minphys size for transfers, which could be greater than 1MB. bp_mapin() does not use the DVMA map array. | And while I've got your attention... I'm currently using mbsetup(), | MBI_ADDR() and mbrelse() as described in the 24 Apr 89 edition of "Writing | Device Drivers". I have skimmed the 27 Mar 90 edition of "Writing Device | Drivers" and the "SunOS4.1 Release Manual", but have been unable to find a | definitive answer to the following question: Are there any changes I | absolutely _must_ make to a DMA driver which runs under SunOS4.0.3 in | order to run it under SunOS4.1? None that I know of.