From 349a9cfc0f167b7290b22def46f7ef353cf1d036 Mon Sep 17 00:00:00 2001
From: Michael Lotz <mmlr@mlotz.ch>
Date: Sat, 12 Apr 2008 06:10:36 +0000
Subject: [PATCH] Use a list of host controller modules instead of using
 open_module_list() and read_next_module_name(). This is ugly and less
 flexible but it allows us to explicitly force an initialization order. As
 detailed by the added comment there seem to be controllers/BIOSes that
 require the EHCI controller to be initialized after the companion host
 controller or else they refuse to publish any high speed devices. This was
 the case for bug #1236 and my laptop when legacy emulation is enabled and any
 device was plugged in at boot. This change fixed the problem for me and
 hopefully closes bug #1236 too.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24926 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 src/add-ons/kernel/bus_managers/usb/Stack.cpp | 30 ++++++++++++-------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/add-ons/kernel/bus_managers/usb/Stack.cpp b/src/add-ons/kernel/bus_managers/usb/Stack.cpp
index d5b4d0a4df..ee47742d02 100644
--- a/src/add-ons/kernel/bus_managers/usb/Stack.cpp
+++ b/src/add-ons/kernel/bus_managers/usb/Stack.cpp
@@ -52,27 +52,37 @@ Stack::Stack()
 	}
 
 	// Check for host controller modules
-	void *moduleList = open_module_list("busses/usb");
-	char moduleName[B_PATH_NAME_LENGTH];
-	size_t bufferSize = sizeof(moduleName);
+	// While using a fixed list of names is inflexible it allows us to control
+	// the order in which we try modules. There are controllers/BIOSes that
+	// require UHCI/OHCI to be initialized before EHCI or otherwise they
+	// refuse to publish any high-speed devices.
+	// On other systems the ordering is probably ensured because the EHCI
+	// controller is required to have a higher PCI function number than the
+	// companion host controllers (per the EHCI specs) and it would therefore
+	// be enumerated as the last item. As this does not apply to us we have to
+	// ensure ordering using another method.
+	const char *moduleNames[] = {
+		"busses/usb/uhci",
+		"busses/usb/ohci",
+		"busses/usb/ehci",
+		NULL
+	};
 
 	TRACE(("USB Stack: looking for host controller modules\n"));
-	while (read_next_module_name(moduleList, moduleName, &bufferSize) == B_OK) {
-		bufferSize = sizeof(moduleName);
-		TRACE(("USB Stack: found module %s\n", moduleName));
+	for (uint32 i = 0; moduleNames[i]; i++) {
+		TRACE(("USB Stack: looking for module %s\n", moduleNames[i]));
 
 		usb_host_controller_info *module = NULL;
-		if (get_module(moduleName, (module_info **)&module) != B_OK)
+		if (get_module(moduleNames[i], (module_info **)&module) != B_OK)
 			continue;
 
+		TRACE(("USB Stack: adding module %s\n", moduleNames[i]));
 		if (module->add_to(this) < B_OK)
 			continue;
 
-		TRACE(("USB Stack: module %s successfully loaded\n", moduleName));
+		TRACE(("USB Stack: module %s successfully loaded\n", moduleNames[i]));
 	}
 
-	close_module_list(moduleList);
-
 	if (fBusManagers.Count() == 0) {
 		TRACE_ERROR(("USB Stack: no bus managers available\n"));
 		return;