On Mon, 26 Apr 2004, Stefan Reinauer wrote: > > Devices with bus master set are allowed to DMA into main memory > > whenever they feel like it so it is dangerous to enable that > > bit indiscriminately. > > --> If at all, it should be done with careful checking.
Here is a possible scenario. You are in linuxbios after somehow falling into it -- i.e., no power up, no reset has happened. Devices for whatever reason are not totally reset, including the ethernet device. The ethernet device is the kind with on-chip buffer queue pointerss. You enable bus master. Chip gets a broadcast packet. It writes it somewhere to memory, over code that won't get run in 2 or 3 weeks. 2 or 3 weeks later, the code is executed. Your kernel goes kaboom! How do you figure out what happened? This is a possible scenario that can happen once you start enabling bus master in the bios. ron _______________________________________________ Linuxbios mailing list [EMAIL PROTECTED] http://www.clustermatic.org/mailman/listinfo/linuxbios
