diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index eea85dafc763..1a0e60e265ea 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -30,6 +30,8 @@
 void pci_update_resource(struct pci_dev *dev, int resno)
 {
 	struct pci_bus_region region;
+	bool disable;
+	u16 cmd;
 	u32 new, check, mask;
 	int reg;
 	enum pci_bar_type type;
@@ -67,6 +69,18 @@ void pci_update_resource(struct pci_dev *dev, int resno)
 		new |= PCI_ROM_ADDRESS_ENABLE;
 	}
 
+	/*
+	 * We can't update a 64-bit BAR atomically, so when possible,
+	 * disable decoding so that a half-updated BAR won't conflict
+	 * with another device.
+	 */
+	disable = (res->flags & IORESOURCE_MEM_64) && !dev->mmio_always_on;
+	if (disable) {
+		pci_read_config_word(dev, PCI_COMMAND, &cmd);
+		pci_write_config_word(dev, PCI_COMMAND,
+				      cmd & ~PCI_COMMAND_MEMORY);
+	}
+
 	pci_write_config_dword(dev, reg, new);
 	pci_read_config_dword(dev, reg, &check);
 
@@ -84,6 +98,10 @@ void pci_update_resource(struct pci_dev *dev, int resno)
 			       "(high %#08x != %#08x)\n", resno, new, check);
 		}
 	}
+
+	if (disable)
+		pci_write_config_word(dev, PCI_COMMAND, cmd);
+
 	res->flags &= ~IORESOURCE_UNSET;
 	dev_dbg(&dev->dev, "BAR %d: set to %pR (PCI address [%#llx-%#llx])\n",
 		resno, res, (unsigned long long)region.start,