[PATCH 1/3] Changed backoff strategy for short reads.
John Van Ostrand
john at vanostrand.com
Tue Sep 5 14:07:55 PDT 2017
Back off was exponential starting at 10ms, which for high baud
rate and no flow-control connections might cause buffer overrun.
This was causing problems when reading Cochran DCs, the hearbeat
byte was being missed.
Signed-off-by: John Van Ostrand <john at vanostrand.com>
---
core/serial_ftdi.c | 7 -------
1 file changed, 7 deletions(-)
diff --git a/core/serial_ftdi.c b/core/serial_ftdi.c
index f8cba95..297d0fa 100644
--- a/core/serial_ftdi.c
+++ b/core/serial_ftdi.c
@@ -395,19 +395,12 @@ static dc_status_t serial_ftdi_read (dc_custom_io_t *io, void *data, size_t size
ERROR (device->context, "%s", ftdi_get_error_string(device->ftdi_ctx));
return DC_STATUS_IO; //Error during read call.
} else if (n == 0) {
- // Exponential backoff.
if (slept >= timeout) {
ERROR(device->context, "%s", "FTDI read timed out.");
return DC_STATUS_TIMEOUT;
}
serial_ftdi_sleep (device, backoff);
slept += backoff;
- backoff *= 2;
- if (backoff + slept > timeout)
- backoff = timeout - slept;
- } else {
- // Reset backoff to 1 on success.
- backoff = 1;
}
nbytes += n;
--
2.4.11
More information about the subsurface
mailing list