printk is a wonderful tool. So wonderful, when I was writing DJGPP
networking code, I had to write a printk-equivalent. I know how useful
that is now: #1 debugging tool = some way to get messages out!
Bottom halves are also pretty neat, so I wrote them for DJGPP too (very
similar to DJGPP's own signal emulation) and used one to get the printks
in irq handlers into the log file safely.
> NT will provide for you mapped and locked pages of the process buffer for
> reads and writes. This allows one to DMA directly into the process buffer
> if you write the driver (and device) to support it. You get a Mdl, which
> you are supposed to pass to the DMA handling code. It is not clear how this
> works for PCI devices, but I haven't put much effort into it. Some Linux
> driver writers have been pining for such a capability.
Some Linux driver writers have been using it already, hacked per-driver
(e.g. sound, special network stuff) except for the locking. User page
locking and blocking for device use would be rather nice.
-- Jamie
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