* MPC8xx IDMA and console garbage
@ 2002-04-23 11:37 Steven Scholz
2002-04-23 11:51 ` Thomas Lange
0 siblings, 1 reply; 3+ messages in thread
From: Steven Scholz @ 2002-04-23 11:37 UTC (permalink / raw)
To: LinuxPPC, Dan Malek
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/
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: MPC8xx IDMA and console garbage
2002-04-23 11:37 MPC8xx IDMA and console garbage Steven Scholz
@ 2002-04-23 11:51 ` Thomas Lange
2002-04-23 12:17 ` Steven Scholz
0 siblings, 1 reply; 3+ messages in thread
From: Thomas Lange @ 2002-04-23 11:51 UTC (permalink / raw)
To: Steven Scholz; +Cc: LinuxPPC
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/
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: MPC8xx IDMA and console garbage
2002-04-23 11:51 ` Thomas Lange
@ 2002-04-23 12:17 ` Steven Scholz
0 siblings, 0 replies; 3+ messages in thread
From: Steven Scholz @ 2002-04-23 12:17 UTC (permalink / raw)
To: Thomas Lange; +Cc: LinuxPPC
Thomas Lange wrote:
>
> 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...
Thanks a million.
That helped. But why? :-(
Cheers,
Steven
** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
^ permalink raw reply [flat|nested] 3+ messages in thread
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2002-04-23 11:51 ` Thomas Lange
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