diff --git a/drivers/staging/comedi/drivers/8255.c b/drivers/staging/comedi/drivers/8255.c
index 48817f087d9758a1e0e40aedce29b25b5ce6bab4..1d53e241e84d94bfd873d44c3de10a06ed83ec31 100644
--- a/drivers/staging/comedi/drivers/8255.c
+++ b/drivers/staging/comedi/drivers/8255.c
@@ -231,7 +231,7 @@ static int subdev_8255_cmdtest(struct comedi_device *dev,
 	err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
-	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, 1);
+	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
 	err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
 
 	if (err)
@@ -298,6 +298,7 @@ int subdev_8255_init_irq(struct comedi_device *dev, struct comedi_subdevice *s,
 	if (ret)
 		return ret;
 
+	s->len_chanlist	= 1;
 	s->do_cmdtest	= subdev_8255_cmdtest;
 	s->do_cmd	= subdev_8255_cmd;
 	s->cancel	= subdev_8255_cancel;
diff --git a/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3120.c b/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3120.c
index 66c24e41d0ffa8367b1c908585740347c73bb90e..7ead23e34e8ebba36e480c527945c0293e8fbfe8 100644
--- a/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3120.c
+++ b/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3120.c
@@ -778,6 +778,7 @@ static int apci3120_ai_cmdtest(struct comedi_device *dev,
 	}
 
 	err |= cfc_check_trigger_arg_min(&cmd->chanlist_len, 1);
+	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
 
 	if (cmd->stop_src == TRIG_COUNT)
 		err |= cfc_check_trigger_arg_min(&cmd->stop_arg, 1);
diff --git a/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3200.c b/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3200.c
index 0536d83738616547fea494e25d959ea59502913c..76a66820775e113c17094c69ca5c33505cf37e1f 100644
--- a/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3200.c
+++ b/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3200.c
@@ -2270,6 +2270,11 @@ static int apci3200_ai_cmdtest(struct comedi_device *dev,
 		apci3200_reset(dev);
 		return 2;
 	}
+
+	/* Step 3: check if arguments are trivially valid */
+
+	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
+
 	/* i_FirstChannel=cmd->chanlist[0]; */
 	s_BoardInfos[dev->minor].i_FirstChannel = cmd->chanlist[0];
 	/* i_LastChannel=cmd->chanlist[1]; */
diff --git a/drivers/staging/comedi/drivers/addi_apci_1032.c b/drivers/staging/comedi/drivers/addi_apci_1032.c
index d6a5424654fca732d655f9c2f134470fc370777b..c242afc9134d6978660ad724c7fdb7b685576d01 100644
--- a/drivers/staging/comedi/drivers/addi_apci_1032.c
+++ b/drivers/staging/comedi/drivers/addi_apci_1032.c
@@ -198,7 +198,7 @@ static int apci1032_cos_cmdtest(struct comedi_device *dev,
 	err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
-	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, 1);
+	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
 	err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
 
 	if (err)
@@ -332,6 +332,7 @@ static int apci1032_auto_attach(struct comedi_device *dev,
 		s->range_table	= &range_digital;
 		s->insn_config	= apci1032_cos_insn_config;
 		s->insn_bits	= apci1032_cos_insn_bits;
+		s->len_chanlist	= 1;
 		s->do_cmdtest	= apci1032_cos_cmdtest;
 		s->do_cmd	= apci1032_cos_cmd;
 		s->cancel	= apci1032_cos_cancel;
diff --git a/drivers/staging/comedi/drivers/amplc_pc236.c b/drivers/staging/comedi/drivers/amplc_pc236.c
index b21d7b48f1daf93ecc8365a21413cbe70023b7b0..2834d0a9342afe866e079f02808c3394868ae0f4 100644
--- a/drivers/staging/comedi/drivers/amplc_pc236.c
+++ b/drivers/staging/comedi/drivers/amplc_pc236.c
@@ -314,7 +314,7 @@ static int pc236_intr_cmdtest(struct comedi_device *dev,
 	err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
-	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, 1);
+	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
 	err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
 
 	if (err)
@@ -402,6 +402,7 @@ static int pc236_common_attach(struct comedi_device *dev, unsigned long iobase,
 			s->maxdata = 1;
 			s->range_table = &range_digital;
 			s->insn_bits = pc236_intr_insn;
+			s->len_chanlist	= 1;
 			s->do_cmdtest = pc236_intr_cmdtest;
 			s->do_cmd = pc236_intr_cmd;
 			s->cancel = pc236_intr_cancel;
diff --git a/drivers/staging/comedi/drivers/comedi_parport.c b/drivers/staging/comedi/drivers/comedi_parport.c
index 9de81c7712fb9103ae9054f54b37abf4dfa2c0b8..50723b9406305c2a12ffb2c69fd44af37cc03172 100644
--- a/drivers/staging/comedi/drivers/comedi_parport.c
+++ b/drivers/staging/comedi/drivers/comedi_parport.c
@@ -181,7 +181,7 @@ static int parport_intr_cmdtest(struct comedi_device *dev,
 	err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
-	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, 1);
+	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
 	err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
 
 	if (err)
@@ -295,6 +295,7 @@ static int parport_attach(struct comedi_device *dev,
 		s->maxdata	= 1;
 		s->range_table	= &range_digital;
 		s->insn_bits	= parport_intr_insn_bits;
+		s->len_chanlist	= 1;
 		s->do_cmdtest	= parport_intr_cmdtest;
 		s->do_cmd	= parport_intr_cmd;
 		s->cancel	= parport_intr_cancel;
diff --git a/drivers/staging/comedi/drivers/dt282x.c b/drivers/staging/comedi/drivers/dt282x.c
index 16cc100531e5dbdb879220c206001c2b8d18cbf7..b1154f0641d2054437b8735d8b44050375f236ce 100644
--- a/drivers/staging/comedi/drivers/dt282x.c
+++ b/drivers/staging/comedi/drivers/dt282x.c
@@ -852,7 +852,7 @@ static int dt282x_ao_cmdtest(struct comedi_device *dev,
 	err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
 	err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg, 5000);
 	err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
-	err |= cfc_check_trigger_arg_max(&cmd->scan_end_arg, 2);
+	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
 
 	if (cmd->stop_src == TRIG_COUNT) {
 		/* any count is allowed */
diff --git a/drivers/staging/comedi/drivers/ni_6527.c b/drivers/staging/comedi/drivers/ni_6527.c
index 860fc81fb11c62bbaabcd714f1dfb2992d729734..2b2dafe29c05f1b04e4e93f1d2de5219c75af701 100644
--- a/drivers/staging/comedi/drivers/ni_6527.c
+++ b/drivers/staging/comedi/drivers/ni_6527.c
@@ -253,7 +253,7 @@ static int ni6527_intr_cmdtest(struct comedi_device *dev,
 	err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
-	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, 1);
+	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
 	err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
 
 	if (err)
@@ -421,6 +421,7 @@ static int ni6527_auto_attach(struct comedi_device *dev,
 		s->range_table	= &range_digital;
 		s->insn_config	= ni6527_intr_insn_config;
 		s->insn_bits	= ni6527_intr_insn_bits;
+		s->len_chanlist	= 1;
 		s->do_cmdtest	= ni6527_intr_cmdtest;
 		s->do_cmd	= ni6527_intr_cmd;
 		s->cancel	= ni6527_intr_cancel;
diff --git a/drivers/staging/comedi/drivers/ni_65xx.c b/drivers/staging/comedi/drivers/ni_65xx.c
index 6e42001f686e3906ff288a73618b12fff59a6e7a..2051a7c5de109d4222e3646a22a4d28db717c474 100644
--- a/drivers/staging/comedi/drivers/ni_65xx.c
+++ b/drivers/staging/comedi/drivers/ni_65xx.c
@@ -473,7 +473,7 @@ static int ni_65xx_intr_cmdtest(struct comedi_device *dev,
 	err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
-	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, 1);
+	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
 	err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
 
 	if (err)
@@ -671,6 +671,7 @@ static int ni_65xx_auto_attach(struct comedi_device *dev,
 	s->n_chan = 1;
 	s->range_table = &range_unknown;
 	s->maxdata = 1;
+	s->len_chanlist	= 1;
 	s->do_cmdtest = ni_65xx_intr_cmdtest;
 	s->do_cmd = ni_65xx_intr_cmd;
 	s->cancel = ni_65xx_intr_cancel;
diff --git a/drivers/staging/comedi/drivers/pcl726.c b/drivers/staging/comedi/drivers/pcl726.c
index cf9568ee46e46f2bcb064c5339baebb3c007aa8e..07ff1e22e61ca67e8bbb7768924c2dcbc19b81ae 100644
--- a/drivers/staging/comedi/drivers/pcl726.c
+++ b/drivers/staging/comedi/drivers/pcl726.c
@@ -197,7 +197,7 @@ static int pcl726_intr_cmdtest(struct comedi_device *dev,
 	err |= cfc_check_trigger_arg_is(&cmd->start_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
 	err |= cfc_check_trigger_arg_is(&cmd->convert_arg, 0);
-	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, 1);
+	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
 	err |= cfc_check_trigger_arg_is(&cmd->stop_arg, 0);
 
 	if (err)
@@ -430,6 +430,7 @@ static int pcl726_attach(struct comedi_device *dev,
 		s->maxdata	= 1;
 		s->range_table	= &range_digital;
 		s->insn_bits	= pcl726_intr_insn_bits;
+		s->len_chanlist	= 1;
 		s->do_cmdtest	= pcl726_intr_cmdtest;
 		s->do_cmd	= pcl726_intr_cmd;
 		s->cancel	= pcl726_intr_cancel;
diff --git a/drivers/staging/comedi/drivers/rtd520.c b/drivers/staging/comedi/drivers/rtd520.c
index 1b1c166c8e9b1681301cd2d3e8f3a516fa896587..e7c2e34624d905a2111f40a7f84965a446c09377 100644
--- a/drivers/staging/comedi/drivers/rtd520.c
+++ b/drivers/staging/comedi/drivers/rtd520.c
@@ -878,6 +878,8 @@ static int rtd_ai_cmdtest(struct comedi_device *dev,
 		err |= cfc_check_trigger_arg_max(&cmd->convert_arg, 9);
 	}
 
+	err |= cfc_check_trigger_arg_is(&cmd->scan_end_arg, cmd->chanlist_len);
+
 	if (cmd->stop_src == TRIG_COUNT) {
 		/* TODO check for rounding error due to counter wrap */
 	} else {