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path: root/drivers/pcmcia/yenta_socket.c
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Diffstat (limited to 'drivers/pcmcia/yenta_socket.c')
-rw-r--r--drivers/pcmcia/yenta_socket.c73
1 files changed, 73 insertions, 0 deletions
diff --git a/drivers/pcmcia/yenta_socket.c b/drivers/pcmcia/yenta_socket.c
index 006749dc8d7..d9d005ec920 100644
--- a/drivers/pcmcia/yenta_socket.c
+++ b/drivers/pcmcia/yenta_socket.c
@@ -1005,6 +1005,77 @@ static void yenta_config_init(struct yenta_socket *socket)
config_writew(socket, CB_BRIDGE_CONTROL, bridge);
}
+/**
+ * yenta_fixup_parent_subordinate - Fix subordinate bus# of the parent bridge
+ * @cardbus_bridge: The PCI bus which the CardBus bridge bridges to
+ *
+ * Checks if devices on the bus which the CardBus bridge bridges to would be
+ * invisible during PCI scans because of a misconfigured subordinate number
+ * of the parent brige - some BIOSes seem to be too lazy to set it right.
+ * Does the fixup carefully by checking how far it can go without conflicts.
+ * See http://bugzilla.kernel.org/show_bug.cgi?id=2944 for more information.
+ */
+static void yenta_fixup_parent_bridge(struct pci_bus *cardbus_bridge)
+{
+ struct list_head *tmp;
+ unsigned char upper_limit;
+ /*
+ * We only check and fix the parent bridge: All systems which need
+ * this fixup that have been reviewed are laptops and the only bridge
+ * which needed fixing was the parent bridge of the CardBus bridge:
+ */
+ struct pci_bus *bridge_to_fix = cardbus_bridge->parent;
+
+ /* Check bus numbers are already set up correctly: */
+ if (bridge_to_fix->subordinate >= cardbus_bridge->subordinate)
+ return; /* The subordinate number is ok, nothing to do */
+
+ if (!bridge_to_fix->parent)
+ return; /* Root bridges are ok */
+
+ /* stay within the limits of the bus range of the parent: */
+ upper_limit = bridge_to_fix->parent->subordinate;
+
+ /* check the bus ranges of all silbling bridges to prevent overlap */
+ list_for_each(tmp, &bridge_to_fix->parent->children) {
+ struct pci_bus * silbling = pci_bus_b(tmp);
+ /*
+ * If the silbling has a higher secondary bus number
+ * and it's secondary is equal or smaller than our
+ * current upper limit, set the new upper limit to
+ * the bus number below the silbling's range:
+ */
+ if (silbling->secondary > bridge_to_fix->subordinate
+ && silbling->secondary <= upper_limit)
+ upper_limit = silbling->secondary - 1;
+ }
+
+ /* Show that the wanted subordinate number is not possible: */
+ if (cardbus_bridge->subordinate > upper_limit)
+ printk(KERN_WARNING "Yenta: Upper limit for fixing this "
+ "bridge's parent bridge: #%02x\n", upper_limit);
+
+ /* If we have room to increase the bridge's subordinate number, */
+ if (bridge_to_fix->subordinate < upper_limit) {
+
+ /* use the highest number of the hidden bus, within limits */
+ unsigned char subordinate_to_assign =
+ min(cardbus_bridge->subordinate, upper_limit);
+
+ printk(KERN_INFO "Yenta: Raising subordinate bus# of parent "
+ "bus (#%02x) from #%02x to #%02x\n",
+ bridge_to_fix->number,
+ bridge_to_fix->subordinate, subordinate_to_assign);
+
+ /* Save the new subordinate in the bus struct of the bridge */
+ bridge_to_fix->subordinate = subordinate_to_assign;
+
+ /* and update the PCI config space with the new subordinate */
+ pci_write_config_byte(bridge_to_fix->self,
+ PCI_SUBORDINATE_BUS, bridge_to_fix->subordinate);
+ }
+}
+
/*
* Initialize a cardbus controller. Make sure we have a usable
* interrupt, and that we can map the cardbus area. Fill in the
@@ -1120,6 +1191,8 @@ static int __devinit yenta_probe (struct pci_dev *dev, const struct pci_device_i
yenta_get_socket_capabilities(socket, isa_interrupts);
printk(KERN_INFO "Socket status: %08x\n", cb_readl(socket, CB_SOCKET_STATE));
+ yenta_fixup_parent_bridge(dev->subordinate);
+
/* Register it with the pcmcia layer.. */
ret = pcmcia_register_socket(&socket->socket);
if (ret == 0) {