From cf2527269fc6f45f685f6597b0246e77c68ce7d1 Mon Sep 17 00:00:00 2001
From: Sebastian Sumpf <sebastian.sumpf@genode-labs.com>
Date: Fri, 28 May 2021 12:48:04 +0200
Subject: [PATCH] qemu-usb: allocate host devices after webcam

Because qemu-usb allocated host devices after 'USB_HOST_DEVICE' in the
object array and 'USB_WEBCAM' is loacated after 'USB_HOST_DEVICE' the
webcam model can overwrite an already allocated pass-through device. As
a solution add the 'USB_FIRST_FREE' to make it clear from where host
devices can be allocated. Also increase the number of supported host
devices to eight.

fixes #4182
---
 repos/libports/src/lib/qemu-usb/qemu_emul.cc | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/repos/libports/src/lib/qemu-usb/qemu_emul.cc b/repos/libports/src/lib/qemu-usb/qemu_emul.cc
index f0330086f3..21538e788b 100644
--- a/repos/libports/src/lib/qemu-usb/qemu_emul.cc
+++ b/repos/libports/src/lib/qemu-usb/qemu_emul.cc
@@ -277,8 +277,9 @@ struct Object_pool
 		USB_BUS,         /* bus driver */
 		USB_DEVICE,      /* USB device driver */
 		USB_HOST_DEVICE, /* USB host device driver */
-		USB_WEBCAM,      /* USB host device driver */
-		MAX = 10          /* host devices (USB_HOST_DEVICE - MAX) */
+		USB_WEBCAM,      /* USB webcam device driver */
+		USB_FIRST_FREE,  /* first free device */
+		MAX = 14         /* host devices (USB_FIRST_FREE to MAX) */
 	};
 
 	bool used[MAX];
@@ -286,7 +287,7 @@ struct Object_pool
 
 	Wrapper *create_object()
 	{
-		for (unsigned i = USB_HOST_DEVICE + 1; i < MAX; i++) {
+		for (unsigned i = USB_FIRST_FREE; i < MAX; i++) {
 			if (used[i] == false) {
 				used[i] = true;
 				return &obj[i];
@@ -297,7 +298,7 @@ struct Object_pool
 
 	void free_object(Wrapper *w)
 	{
-		for (unsigned i = USB_HOST_DEVICE + 1; i < MAX; i++)
+		for (unsigned i = USB_FIRST_FREE; i < MAX; i++)
 			if (w == &obj[i]) {
 				used[i] = false;
 				break;