From: Ian Abbott <abbotti@mev.co.uk>
Date: Thu, 18 Oct 2007 18:01:45 +0000 (+0000)
Subject: Some changes to deal with interrupts before device fully attached.
X-Git-Tag: r0_7_75~15
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=85d4bc62d592f4a4bb60445c94f117e5d5081f27;p=comedi.git

Some changes to deal with interrupts before device fully attached.
---

diff --git a/comedi/drivers/adl_pci9111.c b/comedi/drivers/adl_pci9111.c
index 4bfbcb82..575b9207 100644
--- a/comedi/drivers/adl_pci9111.c
+++ b/comedi/drivers/adl_pci9111.c
@@ -950,13 +950,39 @@ pci9111_interrupt (int irq, void *p_device PT_REGS_ARG)
 	comedi_subdevice *subdevice = dev->read_subdev;
 	comedi_async *async;
 	unsigned long irq_flags;
+	unsigned char intcsr;
+
+	if (!dev->attached)
+	{
+		// Ignore interrupt before device fully attached.
+		// Might not even have allocated subdevices yet!
+		return IRQ_NONE;
+	}
 
 	async = subdevice->async;
 
 	comedi_spin_lock_irqsave (&dev->spinlock, irq_flags);
 
-	if ((inb (dev_private->lcr_io_base + PLX9050_REGISTER_INTERRUPT_CONTROL) &
-	     PLX9050_LINTI1_STATUS) != 0)
+	// Check if we are source of interrupt
+	intcsr = inb (dev_private->lcr_io_base + PLX9050_REGISTER_INTERRUPT_CONTROL);
+	if (!(((intcsr & PLX9050_PCI_INTERRUPT_ENABLE) != 0) &&
+				(((intcsr & (PLX9050_LINTI1_ENABLE |
+					     PLX9050_LINTI1_STATUS)) ==
+				  (PLX9050_LINTI1_ENABLE |
+				   PLX9050_LINTI1_STATUS)) ||
+				 ((intcsr & (PLX9050_LINTI2_ENABLE |
+					     PLX9050_LINTI2_STATUS)) ==
+				  (PLX9050_LINTI2_ENABLE |
+				   PLX9050_LINTI2_STATUS)))))
+	{
+		// Not the source of the interrupt.
+		// (N.B. not using PLX9050_SOFTWARE_INTERRUPT)
+		comedi_spin_unlock_irqrestore (&dev->spinlock, irq_flags);
+		return IRQ_NONE;
+	}
+
+	if ((intcsr & (PLX9050_LINTI1_ENABLE | PLX9050_LINTI1_STATUS)) ==
+			(PLX9050_LINTI1_ENABLE | PLX9050_LINTI1_STATUS))
 	{
 		// Interrupt comes from fifo_half-full signal
 
diff --git a/comedi/drivers/adl_pci9118.c b/comedi/drivers/adl_pci9118.c
index fe081c18..f2b56880 100644
--- a/comedi/drivers/adl_pci9118.c
+++ b/comedi/drivers/adl_pci9118.c
@@ -645,6 +645,9 @@ static irqreturn_t interrupt_pci9118(int irq, void *d PT_REGS_ARG)
 	comedi_device *dev = d;
 	unsigned int	int_daq=0,int_amcc,int_adstat;
 
+	if (!dev->attached)
+		return IRQ_NONE;	// not fully initialized
+
 	int_daq=inl(dev->iobase+PCI9118_INTSRC) & 0xf;		// get IRQ reasons from card
 	int_amcc=inl(devpriv->iobase_a+AMCC_OP_REG_INTCSR);	// get INT register from AMCC chip
 
@@ -1749,6 +1752,8 @@ static int pci9118_attach(comedi_device *dev,comedi_devconfig *it)
 	devpriv->pcidev=pcidev;
 	devpriv->iobase_a=iobase_a;
 
+	pci9118_reset(dev);
+
 	if (it->options[3]&2) irq=0; // user don't want use IRQ
 	if (irq>0)  {
 		if (comedi_request_irq(irq, interrupt_pci9118, IRQF_SHARED, "ADLink PCI-9118", dev)) {
@@ -1869,8 +1874,6 @@ static int pci9118_attach(comedi_device *dev,comedi_devconfig *it)
 	s->io_bits=0xf;		/* all bits output */
 	s->insn_bits=pci9118_insn_bits_do;
 
-	pci9118_reset(dev);
-
 	devpriv->valid=1;
 	devpriv->i8254_osc_base=250;	// 250ns=4MHz
 	devpriv->ai_maskharderr=0x10a;	// default measure crash condition
diff --git a/comedi/drivers/adv_pci1710.c b/comedi/drivers/adv_pci1710.c
index d2ca49af..5e7e1c13 100644
--- a/comedi/drivers/adv_pci1710.c
+++ b/comedi/drivers/adv_pci1710.c
@@ -720,6 +720,9 @@ static irqreturn_t interrupt_service_pci1710(int irq, void *d PT_REGS_ARG)
 	comedi_device *dev = d;
 
 	DPRINTK("adv_pci1710 EDBG: BGN: interrupt_service_pci1710(%d,...)\n",irq);
+	if (!dev->attached)	// is device attached?
+		return IRQ_NONE; // no, exit
+
 	if (!(inw(dev->iobase + PCI171x_STATUS) & Status_IRQ)) 	// is this interrupt from our board?
 		return IRQ_NONE; // no, exit
 
@@ -1299,6 +1302,8 @@ static int pci1710_attach(comedi_device *dev,comedi_devconfig *it)
     		return ret;
 	}
 
+	pci1710_reset(dev);
+
 	if (this_board->have_irq) {
 		if (irq)  {
 			if (comedi_request_irq(irq, interrupt_service_pci1710, IRQF_SHARED, "Advantech PCI-1710", dev)) {
@@ -1404,8 +1409,6 @@ static int pci1710_attach(comedi_device *dev,comedi_devconfig *it)
 
 	devpriv->valid=1;
 
-	pci1710_reset(dev);
-
 	return 0;
 }
 
diff --git a/comedi/drivers/amplc_dio200.c b/comedi/drivers/amplc_dio200.c
index 137347f7..a443950c 100644
--- a/comedi/drivers/amplc_dio200.c
+++ b/comedi/drivers/amplc_dio200.c
@@ -654,7 +654,7 @@ dio200_handle_read_intr(comedi_device *dev, comedi_subdevice *s)
 	triggered = 0;
 
 	comedi_spin_lock_irqsave(&subpriv->spinlock, flags);
-	oldevents = s->async->events;
+	oldevents = s->async ? s->async->events : 0;
 	if (subpriv->has_int_sce) {
 		/*
 		 * Collect interrupt sources that have triggered and disable
@@ -693,7 +693,7 @@ dio200_handle_read_intr(comedi_device *dev, comedi_subdevice *s)
 			outb(cur_enabled, subpriv->iobase);
 		}
 
-		if (subpriv->active) {
+		if (s->async && subpriv->active) {
 			/*
 			 * The command is still active.
 			 *
@@ -740,7 +740,7 @@ dio200_handle_read_intr(comedi_device *dev, comedi_subdevice *s)
 	}
 	comedi_spin_unlock_irqrestore(&subpriv->spinlock, flags);
 
-	if (oldevents != s->async->events) {
+	if (s->async && (oldevents != s->async->events)) {
 		comedi_event(dev, s);
 	}
 
diff --git a/comedi/drivers/amplc_pc236.c b/comedi/drivers/amplc_pc236.c
index 65701e39..0814cc43 100644
--- a/comedi/drivers/amplc_pc236.c
+++ b/comedi/drivers/amplc_pc236.c
@@ -558,7 +558,7 @@ static irqreturn_t pc236_interrupt(int irq,void *d PT_REGS_ARG)
 	int handled;
 
 	handled = pc236_intr_check(dev);
-	if (handled) {
+	if (dev->attached && handled) {
 		comedi_buf_put(s->async,0);
 		s->async->events |= COMEDI_CB_BLOCK | COMEDI_CB_EOS;
 		comedi_event(dev, s);
diff --git a/comedi/drivers/cb_pcidas.c b/comedi/drivers/cb_pcidas.c
index 28f155be..9f9e83e9 100644
--- a/comedi/drivers/cb_pcidas.c
+++ b/comedi/drivers/cb_pcidas.c
@@ -584,6 +584,9 @@ found:
 		devpriv->ao_registers = pci_resource_start(devpriv->pci_dev, AO_BADRINDEX);
 	}
 
+	// disable and clear interrupts on amcc s5933
+	outl(INTCSR_INBOX_INTR_STATUS, devpriv->s5933_config + AMCC_OP_REG_INTCSR);
+
 	// get irq
 	if(comedi_request_irq(devpriv->pci_dev->irq, cb_pcidas_interrupt, IRQF_SHARED, "cb_pcidas", dev ))
 	{
@@ -1505,7 +1508,7 @@ static irqreturn_t cb_pcidas_interrupt(int irq, void *d PT_REGS_ARG)
 
 	if(dev->attached == 0)
 	{
-		comedi_error(dev, "premature interrupt");
+		return IRQ_NONE;
 	}
 
 	async = s->async;
diff --git a/comedi/drivers/cb_pcidas64.c b/comedi/drivers/cb_pcidas64.c
index 42b38d37..1271614c 100644
--- a/comedi/drivers/cb_pcidas64.c
+++ b/comedi/drivers/cb_pcidas64.c
@@ -1749,6 +1749,8 @@ static int attach(comedi_device *dev, comedi_devconfig *it)
 
 	priv(dev)->hw_revision = hw_revision( dev, readw(priv(dev)->main_iobase + HW_STATUS_REG ) );
 	printk(" stc hardware revision %i\n", priv(dev)->hw_revision);
+	init_plx9080(dev);
+	init_stc_registers( dev );
 	// get irq
 	if(comedi_request_irq(pcidev->irq, handle_interrupt, IRQF_SHARED, "cb_pcidas64", dev ))
 	{
@@ -1758,8 +1760,6 @@ static int attach(comedi_device *dev, comedi_devconfig *it)
 	dev->irq = pcidev->irq;
 	printk(" irq %u\n", dev->irq);
 
-	init_plx9080(dev);
-	init_stc_registers( dev );
 	retval = setup_subdevices(dev);
 	if(retval < 0)
 	{
diff --git a/comedi/drivers/das6402.c b/comedi/drivers/das6402.c
index 879a364e..c9ffb5cd 100644
--- a/comedi/drivers/das6402.c
+++ b/comedi/drivers/das6402.c
@@ -158,7 +158,7 @@ static irqreturn_t intr_handler(int irq,void *d PT_REGS_ARG)
 	comedi_device *dev=d;
 	comedi_subdevice *s=dev->subdevices;
 
-	if (devpriv->das6402_ignoreirq){
+	if (!dev->attached || devpriv->das6402_ignoreirq){
 		printk("das6402: BUG: spurious interrupt\n");
 		return IRQ_HANDLED;
 	}
diff --git a/comedi/drivers/dmm32at.c b/comedi/drivers/dmm32at.c
index 58af13ce..730bdb55 100644
--- a/comedi/drivers/dmm32at.c
+++ b/comedi/drivers/dmm32at.c
@@ -843,12 +843,19 @@ static irqreturn_t dmm32at_isr(int irq,void *d PT_REGS_ARG){
 	unsigned short msb, lsb;
 	int i;
 	comedi_device *dev=d;
-        comedi_subdevice *s=dev->read_subdev;
-	comedi_cmd *cmd = &s->async->cmd;
+
+	if (!dev->attached)
+	{
+		comedi_error(dev, "spurious interrupt");
+		return IRQ_HANDLED;
+	}
 
 	intstat = dmm_inb(dev,DMM32AT_INTCLOCK);
 
 	if(intstat & DMM32AT_ADINT){
+		comedi_subdevice *s=dev->read_subdev;
+		comedi_cmd *cmd = &s->async->cmd;
+
 		for(i=0;i<cmd->chanlist_len;i++){
 			/* read data */
 			lsb = dmm_inb(dev,DMM32AT_AILSB);
diff --git a/comedi/drivers/dt2811.c b/comedi/drivers/dt2811.c
index df464ea7..90510350 100644
--- a/comedi/drivers/dt2811.c
+++ b/comedi/drivers/dt2811.c
@@ -255,12 +255,18 @@ static const comedi_lrange *dac_range_types[] =
 #define DT2811_TIMEOUT 5
 
 #if 0
-static void dt2811_interrupt(int irq, void *d PT_REGS_ARG)
+static irqreturn_t dt2811_interrupt(int irq, void *d PT_REGS_ARG)
 {
 	int lo, hi;
 	int data;
 	comedi_device *dev = d;
 
+	if (!dev->attached)
+	{
+		comedi_error(dev, "spurious interrupt");
+		return IRQ_HANDLED;
+	}
+
 	lo = inb(dev->iobase + DT2811_ADDATLO);
 	hi = inb(dev->iobase + DT2811_ADDATHI);
 
@@ -271,6 +277,7 @@ static void dt2811_interrupt(int irq, void *d PT_REGS_ARG)
 		s->async->events |= COMEDI_SB_EOA;
 	}
 	comedi_event(dev, s);
+	return IRQ_HANDLED;
 }
 #endif
 
diff --git a/comedi/drivers/dt2814.c b/comedi/drivers/dt2814.c
index 88b5c54e..d41f157c 100644
--- a/comedi/drivers/dt2814.c
+++ b/comedi/drivers/dt2814.c
@@ -336,9 +336,17 @@ static irqreturn_t dt2814_interrupt(int irq,void *d PT_REGS_ARG)
 {
 	int lo,hi;
 	comedi_device *dev=d;
-	comedi_subdevice *s = dev->subdevices + 0;
+	comedi_subdevice *s;
 	int data;
 
+	if (!dev->attached)
+	{
+		comedi_error(dev, "spurious interrupt");
+		return IRQ_HANDLED;
+	}
+
+	s = dev->subdevices + 0;
+
 	hi=inb(dev->iobase+DT2814_DATA);
 	lo=inb(dev->iobase+DT2814_DATA);
 
diff --git a/comedi/drivers/dt282x.c b/comedi/drivers/dt282x.c
index c04737f7..42454ec5 100644
--- a/comedi/drivers/dt282x.c
+++ b/comedi/drivers/dt282x.c
@@ -578,11 +578,19 @@ static int prep_ao_dma(comedi_device * dev,int dma_index,int n)
 static irqreturn_t dt282x_interrupt(int irq, void *d PT_REGS_ARG)
 {
 	comedi_device *dev = d;
-	comedi_subdevice *s = dev->subdevices+0;
-	comedi_subdevice *s_ao = dev->subdevices+1;
+	comedi_subdevice *s;
+	comedi_subdevice *s_ao;
 	unsigned int supcsr, adcsr, dacsr;
 	int handled = 0;
 
+	if (!dev->attached)
+	{
+		comedi_error(dev, "spurious interrupt");
+		return IRQ_HANDLED;
+	}
+
+	s = dev->subdevices+0;
+	s_ao = dev->subdevices+1;
 	adcsr = inw(dev->iobase + DT2821_ADCSR);
 	dacsr = inw(dev->iobase + DT2821_DACSR);
 	supcsr = inw(dev->iobase + DT2821_SUPCSR);
diff --git a/comedi/drivers/dt3000.c b/comedi/drivers/dt3000.c
index 7ca33c1e..aab9e58e 100644
--- a/comedi/drivers/dt3000.c
+++ b/comedi/drivers/dt3000.c
@@ -333,14 +333,24 @@ static void dt3k_writesingle(comedi_device *dev,unsigned int subsys,
 
 static int debug_n_ints = 0;
 
+// FIXME! Assumes shared interrupt is for this card.
+// What's this debug_n_ints stuff? Obviously needs some work...
 static irqreturn_t dt3k_interrupt(int irq, void *d PT_REGS_ARG)
 {
 	comedi_device *dev = d;
-	comedi_subdevice *s = dev->subdevices + 0;
+	comedi_subdevice *s;
 	unsigned int status;
 
+	if (!dev->attached)
+	{
+		return IRQ_NONE;
+	}
+
+	s = dev->subdevices + 0;
 	status = readw(devpriv->io_addr+DPR_Intr_Flag);
+#ifdef DEBUG
 	debug_intr_flags(status);
+#endif
 
 	if(status & DT3000_ADFULL){
 		dt3k_ai_empty_fifo(dev,s);
diff --git a/comedi/drivers/gsc_hpdi.c b/comedi/drivers/gsc_hpdi.c
index 2f0ed26c..d26a8339 100644
--- a/comedi/drivers/gsc_hpdi.c
+++ b/comedi/drivers/gsc_hpdi.c
@@ -470,10 +470,11 @@ static int init_hpdi( comedi_device *dev )
 	priv(dev)->rx_fifo_size = fifo_size( readl( priv(dev)->hpdi_iobase +
 		RX_FIFO_SIZE_REG ) );
 
+	writel( 0, priv(dev)->hpdi_iobase + INTERRUPT_CONTROL_REG );
+
 	// enable interrupts
 	plx_intcsr_bits = ICS_AERR | ICS_PERR | ICS_PIE | ICS_PLIE | ICS_PAIE | ICS_LIE | ICS_DMA0_E;
 	writel( plx_intcsr_bits, priv(dev)->plx9080_iobase + PLX_INTRCS_REG );
-	writel( 0, priv(dev)->hpdi_iobase + INTERRUPT_CONTROL_REG );
 
 	return 0;
 }
@@ -609,6 +610,8 @@ static int hpdi_attach(comedi_device *dev, comedi_devconfig *it)
 	DEBUG_PRINT(" plx9080 remapped to 0x%p\n", priv(dev)->plx9080_iobase);
 	DEBUG_PRINT(" hpdi remapped to 0x%p\n", priv(dev)->hpdi_iobase);
 
+	init_plx9080(dev);
+
 	// get irq
 	if( comedi_request_irq( pcidev->irq, handle_interrupt, IRQF_SHARED, driver_hpdi.driver_name,
 		 dev ) )
@@ -620,8 +623,6 @@ static int hpdi_attach(comedi_device *dev, comedi_devconfig *it)
 
 	printk(" irq %u\n", dev->irq);
 
-	init_plx9080(dev);
-
 	// alocate pci dma buffers
 	for( i = 0; i < NUM_DMA_BUFFERS; i++ )
 	{
@@ -928,7 +929,17 @@ static irqreturn_t handle_interrupt(int irq, void *d PT_REGS_ARG)
 	uint8_t dma0_status, dma1_status;
 	unsigned long flags;
 
+	if (!dev->attached)
+	{
+		return IRQ_NONE;
+	}
+
 	plx_status = readl( priv(dev)->plx9080_iobase + PLX_INTRCS_REG );
+	if( ( plx_status & ( ICS_DMA0_A | ICS_DMA1_A | ICS_LIA ) ) == 0 )
+	{
+		return IRQ_NONE;
+	}
+
 	hpdi_intr_status = readl( priv(dev)->hpdi_iobase + INTERRUPT_STATUS_REG );
 	hpdi_board_status = readl( priv(dev)->hpdi_iobase + BOARD_STATUS_REG );
 
@@ -938,9 +949,6 @@ static irqreturn_t handle_interrupt(int irq, void *d PT_REGS_ARG)
 	{
 		DEBUG_PRINT("hpdi: intr status 0x%x, ", hpdi_intr_status);
 		writel( hpdi_intr_status, priv(dev)->hpdi_iobase + INTERRUPT_STATUS_REG );
-	}else if( ( plx_status & ( ICS_DMA0_A | ICS_DMA1_A | ICS_LIA ) ) == 0 )
-	{
-		return IRQ_NONE;
 	}
 
 	// spin lock makes sure noone else changes plx dma control reg
diff --git a/comedi/drivers/icp_multi.c b/comedi/drivers/icp_multi.c
index a8a140fb..ae27abbe 100644
--- a/comedi/drivers/icp_multi.c
+++ b/comedi/drivers/icp_multi.c
@@ -926,6 +926,8 @@ static int icp_multi_attach(comedi_device *dev,comedi_devconfig *it)
     		return ret;
 	}
 
+	icp_multi_reset(dev);
+
 	if (this_board->have_irq) {
 		if (irq)  {
 			if (comedi_request_irq(irq, interrupt_service_icp_multi, IRQF_SHARED, "Inova Icp Multi", dev)) {
@@ -1017,8 +1019,6 @@ static int icp_multi_attach(comedi_device *dev,comedi_devconfig *it)
 
 	devpriv->valid = 1;
 
-	icp_multi_reset(dev);
-
 #ifdef ICP_MULTI_EXTDEBUG
 	printk("icp multi EDBG: END: icp_multi_attach(...)\n");
 #endif
diff --git a/comedi/drivers/me4000.c b/comedi/drivers/me4000.c
index d54653dc..aa586436 100644
--- a/comedi/drivers/me4000.c
+++ b/comedi/drivers/me4000.c
@@ -1685,6 +1685,11 @@ static irqreturn_t me4000_ai_isr(int irq, void *dev_id PT_REGS_ARG){
 
     ISR_PDEBUG("me4000_ai_isr() is executed\n");
 
+    if(!dev->attached){
+	    ISR_PDEBUG("me4000_ai_isr() premature interrupt\n");
+	    return IRQ_NONE;
+    }
+
     /* Reset all events */
     s->async->events = 0;
 
diff --git a/comedi/drivers/ni_pcidio.c b/comedi/drivers/ni_pcidio.c
index ab57a782..a95abef8 100644
--- a/comedi/drivers/ni_pcidio.c
+++ b/comedi/drivers/ni_pcidio.c
@@ -494,15 +494,15 @@ static irqreturn_t nidio_interrupt(int irq, void *d PT_REGS_ARG)
 	unsigned int m_status = 0;
 	unsigned long irq_flags;
 
-	status = readb(devpriv->mite->daq_io_addr+Interrupt_And_Window_Status);
-	flags = readb(devpriv->mite->daq_io_addr+Group_1_Flags);
-
 	//interrupcions parasites
 	if(dev->attached == 0){
-		comedi_error(dev,"premature interrupt");
-		async->events |= COMEDI_CB_ERROR|COMEDI_CB_EOA;
+		// assume it's from another card
+		return IRQ_NONE;
 	}
 
+	status = readb(devpriv->mite->daq_io_addr+Interrupt_And_Window_Status);
+	flags = readb(devpriv->mite->daq_io_addr+Group_1_Flags);
+
 	DPRINTK("ni_pcidio_interrupt: status=0x%02x,flags=0x%02x\n",
 		status,flags);
 	ni_pcidio_print_flags(flags);
diff --git a/comedi/drivers/pcl711.c b/comedi/drivers/pcl711.c
index e461c030..54f961e8 100644
--- a/comedi/drivers/pcl711.c
+++ b/comedi/drivers/pcl711.c
@@ -186,12 +186,18 @@ static irqreturn_t pcl711_interrupt(int irq, void *d PT_REGS_ARG)
 	comedi_device *dev = d;
 	comedi_subdevice *s = dev->subdevices + 0;
 
+	if (!dev->attached) {
+		comedi_error(dev, "spurious interrupt");
+		return IRQ_HANDLED;
+	}
+
 	hi = inb(dev->iobase + PCL711_AD_HI);
 	lo = inb(dev->iobase + PCL711_AD_LO);
 	outb(0, dev->iobase + PCL711_CLRINTR);
 
 	data = (hi << 8) | lo;
 
+	/* FIXME! Nothing else sets ntrig! */
 	if (!(--devpriv->ntrig)) {
 		if (this_board->is_8112) {
 			outb(1, dev->iobase + PCL711_MODE);
diff --git a/comedi/drivers/pcl812.c b/comedi/drivers/pcl812.c
index 19099594..d23930dc 100644
--- a/comedi/drivers/pcl812.c
+++ b/comedi/drivers/pcl812.c
@@ -977,6 +977,10 @@ static irqreturn_t interrupt_pcl812(int irq, void *d PT_REGS_ARG)
 {
 	comedi_device *dev = d;
 
+	if (!dev->attached) {
+		comedi_error(dev, "spurious interrupt");
+		return IRQ_HANDLED;
+	}
 	if (devpriv->ai_dma) { return interrupt_pcl812_ai_dma(irq, d); }
 			else { return interrupt_pcl812_ai_int(irq, d); };
 }
diff --git a/comedi/drivers/quatech_daqp_cs.c b/comedi/drivers/quatech_daqp_cs.c
index 4e9cc659..0b5db681 100644
--- a/comedi/drivers/quatech_daqp_cs.c
+++ b/comedi/drivers/quatech_daqp_cs.c
@@ -269,8 +269,8 @@ static int daqp_ai_cancel(comedi_device *dev, comedi_subdevice *s)
 static void daqp_interrupt(int irq, void * dev_id PT_REGS_ARG)
 {
 	local_info_t *local = (local_info_t *)dev_id;
-	comedi_device *dev = local->dev;
-	comedi_subdevice *s = local->s;
+	comedi_device *dev;
+	comedi_subdevice *s;
 	int loop_limit = 10000;
 	int status;
 
@@ -280,12 +280,20 @@ static void daqp_interrupt(int irq, void * dev_id PT_REGS_ARG)
 		return;
 	}
 
+	dev = local->dev;
 	if (dev == NULL) {
 		printk(KERN_WARNING
 		       "daqp_interrupt(): NULL comedi_device.\n");
 		return;
 	}
 
+	if (!dev->attached) {
+		printk(KERN_WARNING
+		       "daqp_interrupt(): comedi_device not yet attached.\n");
+		return;
+	}
+
+	s = local->s;
 	if (s == NULL) {
 		printk(KERN_WARNING
 		       "daqp_interrupt(): NULL comedi_subdevice.\n");
diff --git a/comedi/drivers/rtd520.c b/comedi/drivers/rtd520.c
index 5e8f23d6..7fd11aea 100644
--- a/comedi/drivers/rtd520.c
+++ b/comedi/drivers/rtd520.c
@@ -922,6 +922,27 @@ static int rtd_attach (
     s->n_chan=3;
     s->maxdata=0xffff;
 
+					/* initialize board, per RTD spec */
+					/* also, initialize shadow registers */
+    RtdResetBoard (dev);
+    comedi_udelay (100);			/* needed? */
+    RtdPlxInterruptWrite (dev, 0);
+    RtdInterruptMask (dev,0);		/* and sets shadow */
+    RtdInterruptClearMask (dev,~0);	/* and sets shadow */
+    RtdInterruptClear(dev);		/* clears bits set by mask */
+    RtdInterruptOverrunClear(dev);
+    RtdClearCGT (dev);
+    RtdAdcClearFifo (dev);
+    RtdDacClearFifo (dev,0);
+    RtdDacClearFifo (dev,1);
+					/* clear digital IO fifo*/
+    RtdDioStatusWrite (dev, 0);		/* safe state, set shadow */
+    RtdUtcCtrlPut (dev, 0, 0x30);	/* safe state, set shadow */
+    RtdUtcCtrlPut (dev, 1, 0x30);	/* safe state, set shadow */
+    RtdUtcCtrlPut (dev, 2, 0x30);	/* safe state, set shadow */
+    RtdUtcCtrlPut (dev, 3, 0);		/* safe state, set shadow */
+    /* TODO: set user out source ??? */
+
 	/* check if our interrupt is available and get it */
 	if((ret=comedi_request_irq (devpriv->pci_dev->irq, rtd_interrupt,
 		IRQF_SHARED, "rtd520", dev)) < 0) {
@@ -994,26 +1015,6 @@ static int rtd_attach (
     printk("\n");			/* end configuration line */
 #endif /* USE_DMA */
 
-					/* initialize board, per RTD spec */
-					/* also, initialize shadow registers */
-    RtdResetBoard (dev);
-    comedi_udelay (100);			/* needed? */
-    RtdInterruptMask (dev,0);		/* and sets shadow */
-    RtdInterruptClearMask (dev,~0);	/* and sets shadow */
-    RtdInterruptClear(dev);		/* clears bits set by mask */
-    RtdInterruptOverrunClear(dev);
-    RtdClearCGT (dev);
-    RtdAdcClearFifo (dev);
-    RtdDacClearFifo (dev,0);
-    RtdDacClearFifo (dev,1);
-					/* clear digital IO fifo*/
-    RtdDioStatusWrite (dev, 0);		/* safe state, set shadow */
-    RtdUtcCtrlPut (dev, 0, 0x30);	/* safe state, set shadow */
-    RtdUtcCtrlPut (dev, 1, 0x30);	/* safe state, set shadow */
-    RtdUtcCtrlPut (dev, 2, 0x30);	/* safe state, set shadow */
-    RtdUtcCtrlPut (dev, 3, 0);		/* safe state, set shadow */
-    /* TODO: set user out source ??? */
-
     if (dev->irq) {			/* enable plx9080 interrupts */
 	RtdPlxInterruptWrite (dev, ICS_PIE | ICS_PLIE);
     }
@@ -1509,6 +1510,10 @@ static irqreturn_t rtd_interrupt (
 	u16 fifoStatus;
 	comedi_subdevice *s = dev->subdevices + 0; /* analog in subdevice */
 
+	if (!dev->attached) {
+		return IRQ_NONE;
+	}
+
 	devpriv->intCount++;		/* DEBUG statistics */
 
 	fifoStatus = RtdFifoStatus (dev);