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RE: problems with synchronous serial DMA



Hi,

The synchronous serial port driver does not report to the kernel that it uses dma8 and 9. Therefore this is not indicated in the proc filesystems. This is not critical.

When you use synchronous serial port 1 you have to disable the normal serial port 1 (in kernel config). I think this causes the failure when using non-DMA. If you still have problems send us your kernelconfig and application if possible.

/Mikael

-----Original Message-----
From: owner-dev-etrax@xxxxxxx.com
To: dev-etrax
Sent: 2003-07-25 06:45
Subject: problems with synchronous serial DMA


Hi, I'm trying to get the synchronous serial port to work on ser1 with
DMA 
using the supplied driver in sync_ser.c.  The application is to send PCM
audio 
data in Slave_Output mode to an external DAC/amp.

However, examining /proc/dma I see that DMA 8 and 9 are absent.  This 
contradicts the initialization code found in kernel/head.S.  The entries

for /proc/devices and /proc/interupts are present.  I can do ioctl() on
the the 
device (/dev/syncser0) but write() produces not data (I assume because
of the 
DMA problem).

Also, when I build the kernel without DMA support for ser1, I get a
kernel 
panic because it can't allocate the interupts.

Could someone please provide me with some direction.
Thank you,

David Shenton



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