On 11/05/2014 05:20 PM, Lennart Sorensen wrote:

On Wed, Nov 05, 2014 at 10:33:15AM -0500, Lennart Sorensen wrote:

quoted

Two systems ran 16 hours each so far with no issues.  Pushed 170MB of
data through the pair of serial ports on one system at 230400.

The console on uart3 doesn't appear to be using the dma assuming the
values in /sys for the dma controller and bytes transferred mean anything.
It does mention in dmesg that it allocated dma channels for uart3 though.

Then it should use it :)

How do you tell if it is using dma?

There is omap_8250_tx_dma() and omap_8250_rx_dma(). Both setup
callbacks (the rx+tx _complete). Upon successful DMA transfer you
should see them invoked with bytes transfered (>0).
For RX transfer you need at least trigger bytes in the FIFO within a
given time frame (I think it was 46 bytes and the delay may be up to 2
bytes). If you miss this then DMA for RX won't wire and you purge the
FIFO manually via "timeout-interrupt" (the callback will be invoked
with an error condition and 0 bytes).

Assuming this works for you then one should figure out why the counters
in /sys are not updated…

Sebastian