USB: EHCI: log a warning if ehci-hcd is not loaded first

This patch (as1139) adds a warning to the system log whenever ehci-hcd
is loaded after ohci-hcd or uhci-hcd.  Nowadays most distributions are
pretty good about not doing this; maybe the warning will help convince
anyone still doing it wrong.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>  [2.6.27]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 13 insertions, 2 deletions

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index fcbc1f2b2377..358df2a6c396 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -1046,6 +1046,12 @@ static int __init ehci_hcd_init(void)
                 return -ENODEV;
 
         printk(KERN_INFO "%s: " DRIVER_DESC "\n", hcd_name);
+        set_bit(USB_EHCI_LOADED, &usb_hcds_loaded);
+        if (test_bit(USB_UHCI_LOADED, &usb_hcds_loaded) ||
+                        test_bit(USB_OHCI_LOADED, &usb_hcds_loaded))
+                printk(KERN_WARNING "Warning! ehci_hcd should always be loaded"
+                                " before uhci_hcd and ohci_hcd, not after\n");
+
         pr_debug("%s: block sizes: qh %Zd qtd %Zd itd %Zd sitd %Zd\n",
                  hcd_name,
                  sizeof(struct ehci_qh), sizeof(struct ehci_qtd),
@@ -1053,8 +1059,10 @@ static int __init ehci_hcd_init(void)
 
 #ifdef DEBUG
         ehci_debug_root = debugfs_create_dir("ehci", NULL);
-        if (!ehci_debug_root)
-                return -ENOENT;
+        if (!ehci_debug_root) {
+                retval = -ENOENT;
+                goto err_debug;
+        }
 #endif
 
 #ifdef PLATFORM_DRIVER
@@ -1102,6 +1110,8 @@ clean0:
         debugfs_remove(ehci_debug_root);
         ehci_debug_root = NULL;
 #endif
+err_debug:
+        clear_bit(USB_EHCI_LOADED, &usb_hcds_loaded);
         return retval;
 }
 module_init(ehci_hcd_init);
@@ -1123,6 +1133,7 @@ static void __exit ehci_hcd_cleanup(void)
 #ifdef DEBUG
         debugfs_remove(ehci_debug_root);
 #endif
+        clear_bit(USB_EHCI_LOADED, &usb_hcds_loaded);
 }
 module_exit(ehci_hcd_cleanup);