I also played around with IDMA and noticed the same thing. Serial works ok if you put idma priority below SMC priority. Never investigated further...
/Thomas Steven Scholz wrote: > > Hi there, > > I am trying to get DMA support for MPC8xx IDE. For now I use the IDMA > channel. > It is kind of working although it's not much more than a framework yet. > > BUT: > > My problem right now is this: > > After activating the DMA (e.g. using hdparm -d1 /dev/hda) the output of > my serial console (connected to SMC1) gets garbaged when there is HDD > activity. > > If I telnet into my machine and do e.g. a "fdisk -l /dev/hda" the output > of the serial console looks something like this > > ^PttyS: 80 input overrun(s) > ^P^P^P^P^P^P^P^P^P^ ^PP ^ ^PP ^ ^PP ^P ^P^P^P^P^P^P ^P > ^P^P^P^P^P^P^P^P^P^P^P^P^PttyS: 80 input overrun(s) > > If I redirect console input into a file it contains 0x10 and 0x20 bytes. > > So someone is flooding the serial port (SMC) with the two byte 0x10 and > 0x20 ! > (I might have seen 0x10 and 0xA0 as well.) > > Any ideas? > > Could there be a problem in using the internal ram area. Maybe my IDMA > is conflicting with anyother existing driver (SMC???) ? > > Thanks, > > Steven > ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
