From: Aurelien Jacobs <redacted>
Date: Sat, 9 May 2015 21:06:10 +0000 (+0200)
Subject: scpi-pps: don't fail acquisition start for devices with no CMD_SELECT_CHANNEL
X-Git-Tag: libsigrok-0.4.0~503
X-Git-Url: https://sigrok.org/gitaction?a=commitdiff_plain;h=c1603f4574c8ce9648b51ea587b99cfb0bb02420;p=libsigrok.git

scpi-pps: don't fail acquisition start for devices with no CMD_SELECT_CHANNEL

For devices such as the HP 6632B the following invocation was failing due to
scpi_cmd(sdi, SCPI_CMD_SELECT_CHANNEL, ...) returning SR_OK_CONTINUE.

./sigrok-cli -d scpi-pps:conn=/dev/ttyUSB0:serialcomm=9600/8n1 --continuous
sr: session: sr_session_start: could not start an acquisition (not enough data to decide error status yet)
Failed to start session.
---

diff --git a/src/hardware/scpi-pps/api.c b/src/hardware/scpi-pps/api.c
index d4aa4923..cf6bc65b 100644
--- a/src/hardware/scpi-pps/api.c
+++ b/src/hardware/scpi-pps/api.c
@@ -560,7 +560,7 @@ static int dev_acquisition_start(const struct sr_dev_inst *sdi,
 	/* Prime the pipe with the first channel's fetch. */
 	ch = next_enabled_channel(sdi, NULL);
 	pch = ch->priv;
-	if ((ret = select_channel(sdi, ch)) != SR_OK)
+	if ((ret = select_channel(sdi, ch)) < 0)
 		return ret;
 	if (pch->mq == SR_MQ_VOLTAGE)
 		cmd = SCPI_CMD_GET_MEAS_VOLTAGE;
diff --git a/src/hardware/scpi-pps/protocol.c b/src/hardware/scpi-pps/protocol.c
index 26ff8216..a27089f5 100644
--- a/src/hardware/scpi-pps/protocol.c
+++ b/src/hardware/scpi-pps/protocol.c
@@ -149,7 +149,7 @@ SR_PRIV int select_channel(const struct sr_dev_inst *sdi, struct sr_channel *ch)
 		}
 	}
 
-	if ((ret = scpi_cmd(sdi, SCPI_CMD_SELECT_CHANNEL, new_pch->hwname)) == SR_OK)
+	if ((ret = scpi_cmd(sdi, SCPI_CMD_SELECT_CHANNEL, new_pch->hwname)) >= 0)
 		devc->cur_channel = ch;
 
 	return ret;