drm/radeon/kms: split MSI check into a separate function

This makes it easier to add quirks for certain systems.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_irq_kms.c

@@ -108,6 +108,27 @@ void radeon_driver_irq_uninstall_kms(struct drm_device *dev)
 	radeon_irq_set(rdev);
 }
 
+static bool radeon_msi_ok(struct radeon_device *rdev)
+{
+	/* RV370/RV380 was first asic with MSI support */
+	if (rdev->family < CHIP_RV380)
+		return false;
+
+	/* MSIs don't work on AGP */
+	if (rdev->flags & RADEON_IS_AGP)
+		return false;
+
+	if (rdev->flags & RADEON_IS_IGP) {
+		/* APUs work fine with MSIs */
+		if (rdev->family >= CHIP_PALM)
+			return true;
+		/* lots of IGPs have problems with MSIs */
+		return false;
+	}
+
+	return true;
+}
+
 int radeon_irq_kms_init(struct radeon_device *rdev)
 {
 	int i;
@@ -124,12 +145,8 @@ int radeon_irq_kms_init(struct radeon_device *rdev)
 	}
 	/* enable msi */
 	rdev->msi_enabled = 0;
-	/* MSIs don't seem to work reliably on all IGP
-	 * chips.  Disable MSI on them for now.
-	 */
-	if ((rdev->family >= CHIP_RV380) &&
-	    ((!(rdev->flags & RADEON_IS_IGP)) || (rdev->family >= CHIP_PALM)) &&
-	    (!(rdev->flags & RADEON_IS_AGP))) {
+
+	if (radeon_msi_ok(rdev)) {
 		int ret = pci_enable_msi(rdev->pdev);
 		if (!ret) {
 			rdev->msi_enabled = 1;