#define START_AI_INT   0x04    /* start measure on internal trigger */
 #define STOP_AI_INT    0x08    /* stop measure on internal trigger */
 
-#define EXTTRG_AI      0       /* ext trg is used by AI */
-
 #define PCI9118_HALF_FIFO_SZ   (1024 / 2)
 
 static const struct comedi_lrange pci9118_ai_range = {
                                                 */
        unsigned int dma_actbuf;                /* which buffer is used now */
        struct pci9118_dmabuf dmabuf[2];
-       unsigned char exttrg_users;             /*
-                                                * bit field of external trigger
-                                                * users(0-AI, 1-AO, 2-DI, 3-DO)
-                                                */
        int softsshdelay;               /*
                                         * >0 use software S&H,
                                         * numer is requested delay in ns
        return 0;
 }
 
-static int pci9118_exttrg_add(struct comedi_device *dev, unsigned char source)
+static void pci9118_exttrg_add(struct comedi_device *dev)
 {
        struct pci9118_private *devpriv = dev->private;
 
-       if (source > 3)
-               return -1;                              /* incorrect source */
-       devpriv->exttrg_users |= (1 << source);
        devpriv->int_ctrl |= PCI9118_INT_CTRL_DTRG;
        outl(devpriv->int_ctrl, dev->iobase + PCI9118_INT_CTRL_REG);
        pci9118_amcc_int_ena(dev, true);
-       return 0;
 }
 
-static int pci9118_exttrg_del(struct comedi_device *dev, unsigned char source)
+static void pci9118_exttrg_del(struct comedi_device *dev)
 {
        struct pci9118_private *devpriv = dev->private;
 
-       if (source > 3)
-               return -1;                      /* incorrect source */
-       devpriv->exttrg_users &= ~(1 << source);
-       if (!devpriv->exttrg_users) {   /* shutdown ext trg intterrupts */
-               devpriv->int_ctrl &= ~PCI9118_INT_CTRL_DTRG;
-               if (!devpriv->int_ctrl)
-                       pci9118_amcc_int_ena(dev, false);
-               outl(devpriv->int_ctrl, dev->iobase + PCI9118_INT_CTRL_REG);
-       }
-       return 0;
+       devpriv->int_ctrl &= ~PCI9118_INT_CTRL_DTRG;
+       if (!devpriv->int_ctrl)
+               pci9118_amcc_int_ena(dev, false);
+       outl(devpriv->int_ctrl, dev->iobase + PCI9118_INT_CTRL_REG);
 }
 
 static void pci9118_calc_divisors(char mode, struct comedi_device *dev,
 
        if (devpriv->usedma)
                pci9118_amcc_dma_ena(dev, false);
-       pci9118_exttrg_del(dev, EXTTRG_AI);
+       pci9118_exttrg_del(dev);
        pci9118_start_pacer(dev, 0);    /* stop 8254 counters */
        /* set default config (disable burst and triggers) */
        devpriv->ai_cfg = PCI9118_AI_CFG_PDTRG | PCI9118_AI_CFG_PETRG;
                                /* deactivate EXT trigger */
                                devpriv->ai12_startstop &= ~START_AI_EXT;
                                if (!(devpriv->ai12_startstop & STOP_AI_EXT))
-                                       pci9118_exttrg_del(dev, EXTTRG_AI);
+                                       pci9118_exttrg_del(dev);
 
                                /* start pacer */
                                pci9118_start_pacer(dev, devpriv->ai_do);
                        } else if (devpriv->ai12_startstop & STOP_AI_EXT) {
                                /* deactivate EXT trigger */
                                devpriv->ai12_startstop &= ~STOP_AI_EXT;
-                               pci9118_exttrg_del(dev, EXTTRG_AI);
+                               pci9118_exttrg_del(dev);
 
                                /* on next interrupt measure will stop */
                                devpriv->ai_neverending = 0;
        }
 
        if (devpriv->ai12_startstop)
-               pci9118_exttrg_add(dev, EXTTRG_AI);
+               pci9118_exttrg_add(dev);
                                                /* activate EXT trigger */
 
        if ((devpriv->ai_do == 1) || (devpriv->ai_do == 2))
        }
 
        if (devpriv->ai12_startstop) {
-               pci9118_exttrg_add(dev, EXTTRG_AI);
+               pci9118_exttrg_add(dev);
                                                /* activate EXT trigger */
        }