On Sun, 30 Dec 2007 19:14:40 +0100 Rene Herman <[EMAIL PROTECTED]> wrote:
> On 30-12-07 17:48, Alan Cox wrote: > > > For processors with TSC I think we should aim for 2.6.25 to do this and > > to have the major other _p fixups done. I pity whoever does stuff like > > the scc drivers but most of the rest isn't too bad. > > I'm by the way looking at drivers/net/wd.c which my 386 uses for its dual > mode NE2000/WD8013 clone ISA NIC and while it specifically needs no delay at > all it seems, the mixed use of out and outb_p seems to suggest that someone > once thought about that. Would you advice sticking in a udelay(2) manually > there? I dug out the reference drivers. The reference drivers use the delay and the 8390 datasheet confirms it is neccessary. The Crynwr driver has some interesting things to say | The National 8390 Chip (NIC) requires 4 bus clocks between successive | chip selects (National DP8390 Data Sheet Addendum, June 1990) Also " To establish a minimum delay, an I/O instruction must be used. A good rule of ; thumb is that ISA I/O instructions take ~1.0 microseconds and MCA I/O ; instructions take ~0.5 microseconds. Reading the NMI Status Register (0x61) ; is a good way to pause on all machines." But all the official drivers use pauses and the manual says they are needed for correct, reliable behaviour - at least with a genuine 8390. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
