From Eric Anholt: some cleanups from AlanH:

- Tie the DRM to a specific device: setunique no longer succeeds when given
a busid that doesn't correspond to the device the DRM is attached to. This
is a breaking of backwards-compatibility only for the multiple-DRI-head case
with X Servers that don't use interface 1.1.
- Move irq_busid to drm_irq.h and make it only return the IRQ for the current
device. Retains compatibility with previous X Servers, cleans up unnecessary
code. This means no irq_busid on !__HAVE_IRQ, but can be changed if
necessary.
- Bump interface version to 1.2. This version when set signifies that the
control ioctl should ignore the irq number passed in and enable the
interrupt handler for the attached device. Otherwise it errors out when
the passed-in irq is not equal to the device's.
- Store the highest version the interface has been set to in the device. 

drivers/char/drm/drmP.h

@@ -324,6 +324,7 @@ do {											\
 #define DRM_BUFCOUNT(x) ((x)->count - DRM_LEFTCOUNT(x))
 #define DRM_WAITCOUNT(dev,idx) DRM_BUFCOUNT(&dev->queuelist[idx]->waitlist)
 
+#define DRM_IF_VERSION(maj, min) (maj << 16 | min)
 /**
  * Get the private SAREA mapping.
  *
@@ -628,6 +629,7 @@ typedef struct drm_device {
 	dev_t		  device;	/**< Device number for mknod */
 	char		  *devname;	/**< For /proc/interrupts */
 	int		  minor;        /**< Minor device number */
+	int		  if_version;	/**< Highest interface version set */
 
 	int		  blocked;	/**< Blocked due to VC switch? */
 	struct proc_dir_entry *root;	/**< Root for this device's entries */
@@ -685,6 +687,7 @@ typedef struct drm_device {
 	/** \name Context support */
 	/*@{*/
 	int		  irq;		/**< Interrupt used by board */
+	int		  irq_enabled;	/**< True if irq handler is enabled */
 	__volatile__ long context_flag;	/**< Context swapping flag */
 	__volatile__ long interrupt_flag; /**< Interruption handler flag */
 	__volatile__ long dma_flag;	/**< DMA dispatch flag */
@@ -720,7 +723,12 @@ typedef struct drm_device {
 #if __REALLY_HAVE_AGP
 	drm_agp_head_t    *agp;	/**< AGP data */
 #endif
-	struct pci_dev *pdev;		/**< PCI device structure */
+
+	struct pci_dev    *pdev;	/**< PCI device structure */
+	int               pci_domain;	/**< PCI bus domain number */
+	int               pci_bus;	/**< PCI bus number */
+	int               pci_slot;	/**< PCI slot number */
+	int               pci_func;	/**< PCI function number */
 #ifdef __alpha__
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,3)
 	struct pci_controler *hose;
@@ -810,8 +818,8 @@ extern int           DRM(unbind_agp)(DRM_AGP_MEM *handle);
 #endif
 
 				/* Misc. IOCTL support (drm_ioctl.h) */
-extern int	     DRM(irq_busid)(struct inode *inode, struct file *filp,
-				    unsigned int cmd, unsigned long arg);
+extern int	     DRM(irq_by_busid)(struct inode *inode, struct file *filp,
+				       unsigned int cmd, unsigned long arg);
 extern int	     DRM(getunique)(struct inode *inode, struct file *filp,
 				    unsigned int cmd, unsigned long arg);
 extern int	     DRM(setunique)(struct inode *inode, struct file *filp,
@@ -916,7 +924,7 @@ extern int           DRM(control)( struct inode *inode, struct file *filp,
 				   unsigned int cmd, unsigned long arg );
 #endif
 #if __HAVE_IRQ
-extern int           DRM(irq_install)( drm_device_t *dev, int irq );
+extern int           DRM(irq_install)( drm_device_t *dev );
 extern int           DRM(irq_uninstall)( drm_device_t *dev );
 extern irqreturn_t   DRM(irq_handler)( DRM_IRQ_ARGS );
 extern void          DRM(driver_irq_preinstall)( drm_device_t *dev );

drivers/char/drm/drm_drv.h

@@ -173,7 +173,9 @@ static drm_ioctl_desc_t		  DRM(ioctls)[] = {
 	[DRM_IOCTL_NR(DRM_IOCTL_VERSION)]       = { DRM(version),     0, 0 },
 	[DRM_IOCTL_NR(DRM_IOCTL_GET_UNIQUE)]    = { DRM(getunique),   0, 0 },
 	[DRM_IOCTL_NR(DRM_IOCTL_GET_MAGIC)]     = { DRM(getmagic),    0, 0 },
-	[DRM_IOCTL_NR(DRM_IOCTL_IRQ_BUSID)]     = { DRM(irq_busid),   0, 1 },
+#if __HAVE_IRQ
+	[DRM_IOCTL_NR(DRM_IOCTL_IRQ_BUSID)]     = { DRM(irq_by_busid), 0, 1 },
+#endif
 	[DRM_IOCTL_NR(DRM_IOCTL_GET_MAP)]       = { DRM(getmap),      0, 0 },
 	[DRM_IOCTL_NR(DRM_IOCTL_GET_CLIENT)]    = { DRM(getclient),   0, 0 },
 	[DRM_IOCTL_NR(DRM_IOCTL_GET_STATS)]     = { DRM(getstats),    0, 0 },
@@ -334,7 +336,7 @@ static int DRM(setup)( drm_device_t *dev )
 	dev->queue_reserved = 0;
 	dev->queue_slots = 0;
 	dev->queuelist = NULL;
-	dev->irq = 0;
+	dev->irq_enabled = 0;
 	dev->context_flag = 0;
 	dev->interrupt_flag = 0;
 	dev->dma_flag = 0;
@@ -342,6 +344,7 @@ static int DRM(setup)( drm_device_t *dev )
 	dev->last_switch = 0;
 	dev->last_checked = 0;
 	init_waitqueue_head( &dev->context_wait );
+	dev->if_version = 0;
 
 	dev->ctx_start = 0;
 	dev->lck_start = 0;
@@ -389,7 +392,7 @@ static int DRM(takedown)( drm_device_t *dev )
 
 	DRIVER_PRETAKEDOWN();
 #if __HAVE_IRQ
-	if ( dev->irq ) DRM(irq_uninstall)( dev );
+	if ( dev->irq_enabled ) DRM(irq_uninstall)( dev );
 #endif
 
 	down( &dev->struct_sem );
@@ -573,7 +576,14 @@ static int DRM(probe)(struct pci_dev *pdev)
 	dev->pdev   = pdev;
 #ifdef __alpha__
 	dev->hose   = pdev->sysdata;
+	dev->pci_domain = dev->hose->bus->number;
+#else
+	dev->pci_domain = 0;
 #endif
+	dev->pci_bus = pdev->bus->number;
+	dev->pci_slot = PCI_SLOT(pdev->devfn);
+	dev->pci_func = PCI_FUNC(pdev->devfn);
+	dev->irq = pdev->irq;
 
 	DRIVER_PREINIT();
 
@@ -626,7 +636,7 @@ static int DRM(probe)(struct pci_dev *pdev)
  *
  * \return zero on success or a negative number on failure.
  *
- * Allocates and initialize an array of drm_device structures, and attempts to
+ * Initializes an array of drm_device structures, and attempts to
  * initialize all available devices, using consecutive minors, registering the
  * stubs and initializing the AGP device.
  * 

drivers/char/drm/drm_ioctl.h

@@ -37,69 +37,6 @@
 
 #include "linux/pci.h"
 
-/**
- * Get interrupt from bus id.
- * 
- * \param inode device inode.
- * \param filp file pointer.
- * \param cmd command.
- * \param arg user argument, pointing to a drm_irq_busid structure.
- * \return zero on success or a negative number on failure.
- * 
- * Finds the PCI device with the specified bus id and gets its IRQ number.
- */
-int DRM(irq_busid)(struct inode *inode, struct file *filp,
-		   unsigned int cmd, unsigned long arg)
-{
-	drm_irq_busid_t p;
-	struct pci_dev	*dev;
-
-	if (copy_from_user(&p, (drm_irq_busid_t *)arg, sizeof(p)))
-		return -EFAULT;
-#ifdef __alpha__
-	{
-		int domain = p.busnum >> 8;
-		p.busnum &= 0xff;
-
-		/*
-		 * Find the hose the device is on (the domain number is the
-		 * hose index) and offset the bus by the root bus of that
-		 * hose.
-		 */
-                for(dev = pci_find_device(PCI_ANY_ID,PCI_ANY_ID,NULL);
-                    dev;
-                    dev = pci_find_device(PCI_ANY_ID,PCI_ANY_ID,dev)) {
-			struct pci_controller *hose = dev->sysdata;
-			
-			if (hose->index == domain) {
-				p.busnum += hose->bus->number;
-				break;
-			}
-		}
-	}
-#endif
-	dev = pci_find_slot(p.busnum, PCI_DEVFN(p.devnum, p.funcnum));
-	if (!dev) {
-		DRM_ERROR("pci_find_slot failed for %d:%d:%d\n",
-			  p.busnum, p.devnum, p.funcnum);
-		p.irq = 0;
-		goto out;
-	}			
-	if (pci_enable_device(dev) != 0) {
-		DRM_ERROR("pci_enable_device failed for %d:%d:%d\n",
-			  p.busnum, p.devnum, p.funcnum);
-		p.irq = 0;
-		goto out;
-	}		
-	p.irq = dev->irq;
- out:
-	DRM_DEBUG("%d:%d:%d => IRQ %d\n",
-		  p.busnum, p.devnum, p.funcnum, p.irq);
-	if (copy_to_user((drm_irq_busid_t *)arg, &p, sizeof(p)))
-		return -EFAULT;
-	return 0;
-}
-
 /**
  * Get the bus id.
  * 
@@ -139,9 +76,9 @@ int DRM(getunique)(struct inode *inode, struct file *filp,
  * \param arg user argument, pointing to a drm_unique structure.
  * \return zero on success or a negative number on failure.
  *
- * Copies the bus id from userspace into drm_device::unique, and searches for
- * the respective PCI device, updating drm_device::pdev.  Deprecated in
- * interface version 1.1 and will return EBUSY when setversion has requested
+ * Copies the bus id from userspace into drm_device::unique, and verifies that
+ * it matches the device this DRM is attached to (EINVAL otherwise).  Deprecated
+ * in interface version 1.1 and will return EBUSY when setversion has requested
  * version 1.1 or greater.
  */
 int DRM(setunique)(struct inode *inode, struct file *filp,
@@ -150,6 +87,7 @@ int DRM(setunique)(struct inode *inode, struct file *filp,
 	drm_file_t	 *priv	 = filp->private_data;
 	drm_device_t	 *dev	 = priv->dev;
 	drm_unique_t	 u;
+	int		 domain, bus, slot, func, ret;
 
 	if (dev->unique_len || dev->unique) return -EBUSY;
 
@@ -167,55 +105,25 @@ int DRM(setunique)(struct inode *inode, struct file *filp,
 
 	dev->devname = DRM(alloc)(strlen(dev->name) + strlen(dev->unique) + 2,
 				  DRM_MEM_DRIVER);
-	if(!dev->devname) {
-		DRM(free)(dev->devname, sizeof(*dev->devname), DRM_MEM_DRIVER);
+	if (!dev->devname)
 		return -ENOMEM;
-	}
-	sprintf(dev->devname, "%s@%s", dev->name, dev->unique);
 
-	do {
-		struct pci_dev *pci_dev;
-                int domain, b, d, f;
-                char *p;
- 
-                for(p = dev->unique; p && *p && *p != ':'; p++);
-                if (!p || !*p) break;
-                b = (int)simple_strtoul(p+1, &p, 10);
-                if (*p != ':') break;
-                d = (int)simple_strtoul(p+1, &p, 10);
-                if (*p != ':') break;
-                f = (int)simple_strtoul(p+1, &p, 10);
-                if (*p) break;
- 
-		domain = b >> 8;
-		b &= 0xff;
-
-#ifdef __alpha__
-		/*
-		 * Find the hose the device is on (the domain number is the
-		 * hose index) and offset the bus by the root bus of that
-		 * hose.
-		 */
-                for(pci_dev = pci_find_device(PCI_ANY_ID,PCI_ANY_ID,NULL);
-                    pci_dev;
-                    pci_dev = pci_find_device(PCI_ANY_ID,PCI_ANY_ID,pci_dev)) {
-			struct pci_controller *hose = pci_dev->sysdata;
-			
-			if (hose->index == domain) {
-				b += hose->bus->number;
-				break;
-			}
-		}
-#endif
+	sprintf(dev->devname, "%s@%s", dev->name, dev->unique);
 
-                pci_dev = pci_find_slot(b, PCI_DEVFN(d,f));
-                if (pci_dev) {
-			dev->pdev = pci_dev;
-#ifdef __alpha__
-			dev->hose = pci_dev->sysdata;
-#endif
-		}
-        } while(0);
+	/* Return error if the busid submitted doesn't match the device's actual
+	 * busid.
+	 */
+	ret = sscanf(dev->unique, "PCI:%d:%d:%d", &bus, &slot, &func);
+	if (ret != 3)
+		return DRM_ERR(EINVAL);
+	domain = bus >> 8;
+	bus &= 0xff;
+	
+	if ((domain != dev->pci_domain) ||
+	    (bus != dev->pci_bus) ||
+	    (slot != dev->pci_slot) ||
+	    (func != dev->pci_func))
+		return -EINVAL;
 
 	return 0;
 }
@@ -231,21 +139,8 @@ DRM(set_busid)(drm_device_t *dev)
 	if (dev->unique == NULL)
 		return ENOMEM;
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,74)
-	snprintf(dev->unique, dev->unique_len, "pci:%s", pci_name(dev->pdev));
-#else
-	{
-		int domain = 0;
-#ifdef __alpha__
-		struct pci_controller *hose = pci_dev->sysdata;
-
-		domain = hose->bus->number;
-#endif
-		snprintf(dev->unique, dev->unique_len, "pci:%04x:%02x:%02x.%d",
-			domain, dev->pdev->bus->number,
-			PCI_SLOT(dev->pdev->devfn), PCI_FUNC(dev->pdev->devfn));
-	}
-#endif
+	snprintf(dev->unique, dev->unique_len, "pci:%04x:%02x:%02x.%d",
+		dev->pci_domain, dev->pci_bus, dev->pci_slot, dev->pci_func);
 
 	return 0;
 }
@@ -397,26 +292,31 @@ int DRM(getstats)( struct inode *inode, struct file *filp,
 	return 0;
 }
 
+#define DRM_IF_MAJOR	1
+#define DRM_IF_MINOR	2
+
 int DRM(setversion)(DRM_IOCTL_ARGS)
 {
 	DRM_DEVICE;
 	drm_set_version_t sv;
 	drm_set_version_t retv;
+	int if_version;
 
 	DRM_COPY_FROM_USER_IOCTL(sv, (drm_set_version_t *)data, sizeof(sv));
 
-	retv.drm_di_major = 1;
-	retv.drm_di_minor = 1;
+	retv.drm_di_major = DRM_IF_MAJOR;
+	retv.drm_di_minor = DRM_IF_MINOR;
 	retv.drm_dd_major = DRIVER_MAJOR;
 	retv.drm_dd_minor = DRIVER_MINOR;
-	
+
 	DRM_COPY_TO_USER_IOCTL((drm_set_version_t *)data, retv, sizeof(sv));
 
 	if (sv.drm_di_major != -1) {
-		if (sv.drm_di_major != 1 || sv.drm_di_minor < 0)
-			return EINVAL;
-		if (sv.drm_di_minor > 1)
+		if (sv.drm_di_major != DRM_IF_MAJOR ||
+		    sv.drm_di_minor < 0 || sv.drm_di_minor > DRM_IF_MINOR)
 			return EINVAL;
+		if_version = DRM_IF_VERSION(sv.drm_di_major, sv.drm_dd_minor);
+		dev->if_version = DRM_MAX(if_version, dev->if_version);
 		if (sv.drm_di_minor >= 1) {
 			/*
 			 * Version 1.1 includes tying of DRM to specific device
@@ -426,12 +326,11 @@ int DRM(setversion)(DRM_IOCTL_ARGS)
 	}
 
 	if (sv.drm_dd_major != -1) {
-		if (sv.drm_dd_major != DRIVER_MAJOR || sv.drm_dd_minor < 0)
-			return EINVAL;
-		if (sv.drm_dd_minor > DRIVER_MINOR)
+		if (sv.drm_dd_major != DRIVER_MAJOR ||
+		    sv.drm_dd_minor < 0 || sv.drm_dd_minor > DRIVER_MINOR)
 			return EINVAL;
 #ifdef DRIVER_SETVERSION
-		DRIVER_SETVERSION(dev, sv);
+		DRIVER_SETVERSION(dev, &sv);
 #endif
 	}
 	return 0;

drivers/char/drm/drm_irq.h

@@ -48,6 +48,44 @@
 #define DRM_IRQ_TYPE		0
 #endif
 
+/**
+ * Get interrupt from bus id.
+ * 
+ * \param inode device inode.
+ * \param filp file pointer.
+ * \param cmd command.
+ * \param arg user argument, pointing to a drm_irq_busid structure.
+ * \return zero on success or a negative number on failure.
+ * 
+ * Finds the PCI device with the specified bus id and gets its IRQ number.
+ * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
+ * to that of the device that this DRM instance attached to.
+ */
+int DRM(irq_by_busid)(struct inode *inode, struct file *filp,
+		   unsigned int cmd, unsigned long arg)
+{
+	drm_file_t *priv = filp->private_data;
+	drm_device_t *dev = priv->dev;
+	drm_irq_busid_t p;
+
+	if (copy_from_user(&p, (drm_irq_busid_t *)arg, sizeof(p)))
+		return -EFAULT;
+
+	if ((p.busnum >> 8) != dev->pci_domain ||
+	    (p.busnum & 0xff) != dev->pci_bus ||
+	    p.devnum != dev->pci_slot ||
+	    p.funcnum != dev->pci_func)
+		return -EINVAL;
+
+	p.irq = dev->irq;
+
+	DRM_DEBUG("%d:%d:%d => IRQ %d\n",
+		  p.busnum, p.devnum, p.funcnum, p.irq);
+	if (copy_to_user((drm_irq_busid_t *)arg, &p, sizeof(p)))
+		return -EFAULT;
+	return 0;
+}
+
 #if __HAVE_IRQ
 
 /**
@@ -60,11 +98,11 @@
  * \c DRM(driver_irq_preinstall)() and \c DRM(driver_irq_postinstall)() functions
  * before and after the installation.
  */
-int DRM(irq_install)( drm_device_t *dev, int irq )
+int DRM(irq_install)( drm_device_t *dev )
 {
 	int ret;
-
-	if ( !irq )
+ 
+	if ( dev->irq == 0 )
 		return -EINVAL;
 
 	down( &dev->struct_sem );
@@ -75,22 +113,20 @@ int DRM(irq_install)( drm_device_t *dev, int irq )
 		return -EINVAL;
 	}
 
-	if ( dev->irq ) {
+	if ( dev->irq_enabled ) {
 		up( &dev->struct_sem );
 		return -EBUSY;
 	}
-	dev->irq = irq;
+	dev->irq_enabled = 1;
 	up( &dev->struct_sem );
 
-	DRM_DEBUG( "%s: irq=%d\n", __FUNCTION__, irq );
-
-	dev->context_flag = 0;
-	dev->interrupt_flag = 0;
-	dev->dma_flag = 0;
+	DRM_DEBUG( "%s: irq=%d\n", __FUNCTION__, dev->irq );
 
+#if __HAVE_DMA
 	dev->dma->next_buffer = NULL;
 	dev->dma->next_queue = NULL;
 	dev->dma->this_buffer = NULL;
+#endif
 
 #if __HAVE_IRQ_BH
 	INIT_WORK(&dev->work, DRM(irq_immediate_bh), dev);
@@ -114,7 +150,7 @@ int DRM(irq_install)( drm_device_t *dev, int irq )
 			   DRM_IRQ_TYPE, dev->devname, dev );
 	if ( ret < 0 ) {
 		down( &dev->struct_sem );
-		dev->irq = 0;
+		dev->irq_enabled = 0;
 		up( &dev->struct_sem );
 		return ret;
 	}
@@ -134,21 +170,21 @@ int DRM(irq_install)( drm_device_t *dev, int irq )
  */
 int DRM(irq_uninstall)( drm_device_t *dev )
 {
-	int irq;
+	int irq_enabled;
 
 	down( &dev->struct_sem );
-	irq = dev->irq;
-	dev->irq = 0;
+	irq_enabled = dev->irq_enabled;
+	dev->irq_enabled = 0;
 	up( &dev->struct_sem );
 
-	if ( !irq )
+	if ( !irq_enabled )
 		return -EINVAL;
 
-	DRM_DEBUG( "%s: irq=%d\n", __FUNCTION__, irq );
+	DRM_DEBUG( "%s: irq=%d\n", __FUNCTION__, dev->irq );
 
 	DRM(driver_irq_uninstall)( dev );
 
-	free_irq( irq, dev );
+	free_irq( dev->irq, dev );
 
 	return 0;
 }
@@ -176,7 +212,10 @@ int DRM(control)( struct inode *inode, struct file *filp,
 
 	switch ( ctl.func ) {
 	case DRM_INST_HANDLER:
-		return DRM(irq_install)( dev, ctl.irq );
+		if (dev->if_version < DRM_IF_VERSION(1, 2) &&
+		    ctl.irq != dev->irq)
+			return -EINVAL;
+		return DRM(irq_install)( dev );
 	case DRM_UNINST_HANDLER:
 		return DRM(irq_uninstall)( dev );
 	default:

drivers/char/drm/gamma_dma.c

@@ -661,7 +661,7 @@ int gamma_do_cleanup_dma( drm_device_t *dev )
 	 * may not have been called from userspace and after dev_private
 	 * is freed, it's too late.
 	 */
-	if ( dev->irq ) DRM(irq_uninstall)(dev);
+	if ( dev->irq_enabled ) DRM(irq_uninstall)(dev);
 #endif
 
 	if ( dev->dev_private ) {

drivers/char/drm/i810_dma.c

@@ -237,7 +237,7 @@ int i810_dma_cleanup(drm_device_t *dev)
 	 * may not have been called from userspace and after dev_private
 	 * is freed, it's too late.
 	 */
-	if (dev->irq) DRM(irq_uninstall)(dev);
+	if ( dev->irq_enabled ) DRM(irq_uninstall)(dev);
 #endif
 
 	if (dev->dev_private) {

drivers/char/drm/i830_dma.c

@@ -236,7 +236,7 @@ int i830_dma_cleanup(drm_device_t *dev)
 	 * may not have been called from userspace and after dev_private
 	 * is freed, it's too late.
 	 */
-	if (dev->irq) DRM(irq_uninstall)(dev);
+	if ( dev->irq_enabled ) DRM(irq_uninstall)(dev);
 #endif
 
 	if (dev->dev_private) {
@@ -1539,7 +1539,7 @@ int i830_getparam( struct inode *inode, struct file *filp, unsigned int cmd,
 
 	switch( param.param ) {
 	case I830_PARAM_IRQ_ACTIVE:
-		value = dev->irq ? 1 : 0;
+		value = dev->irq_enabled;
 		break;
 	default:
 		return -EINVAL;

drivers/char/drm/mga_dma.c

@@ -644,7 +644,7 @@ int mga_do_cleanup_dma( drm_device_t *dev )
 	 * may not have been called from userspace and after dev_private
 	 * is freed, it's too late.
 	 */
-	if ( dev->irq ) DRM(irq_uninstall)(dev);
+	if ( dev->irq_enabled ) DRM(irq_uninstall)(dev);
 #endif
 
 	if ( dev->dev_private ) {

drivers/char/drm/r128_cce.c

@@ -620,7 +620,7 @@ int r128_do_cleanup_cce( drm_device_t *dev )
 	 * may not have been called from userspace and after dev_private
 	 * is freed, it's too late.
 	 */
-	if ( dev->irq ) DRM(irq_uninstall)(dev);
+	if ( dev->irq_enabled ) DRM(irq_uninstall)(dev);
 #endif
 
 	if ( dev->dev_private ) {

drivers/char/drm/radeon_cp.c

@@ -1287,7 +1287,7 @@ int radeon_do_cleanup_cp( drm_device_t *dev )
 	 * may not have been called from userspace and after dev_private
 	 * is freed, it's too late.
 	 */
-	if ( dev->irq ) DRM(irq_uninstall)(dev);
+	if ( dev->irq_enabled ) DRM(irq_uninstall)(dev);
 #endif
 
 	if ( dev->dev_private ) {