From 96d9f5d317c25ead15dd9ec509758e3d277fd362 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Josef=20S=C3=B6ntgen?= <jws@sysret.de>
Date: Fri, 1 Nov 2024 17:08:24 +0100
Subject: [PATCH] usb: consider alternate setting in endpoint select

When constructing an Usb::Interface and implicitly corresponding
Usb::Endpoint instances only select endpoints relevant for the
given alternate setting.

The libusb has to be changed to delegate the correct alternate
setting to the constructor too.

Fix genodelabs/genode#5394
---
 repos/libports/src/lib/libusb/genode_usb_raw.cc | 17 ++++++++++++++---
 repos/os/include/usb_session/device.h           |  2 ++
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/repos/libports/src/lib/libusb/genode_usb_raw.cc b/repos/libports/src/lib/libusb/genode_usb_raw.cc
index 57845480dd..42672b7621 100644
--- a/repos/libports/src/lib/libusb/genode_usb_raw.cc
+++ b/repos/libports/src/lib/libusb/genode_usb_raw.cc
@@ -58,7 +58,7 @@ struct Usb_device
 
 		Usb_device &_device;
 
-		Interface(Usb_device &device, uint8_t idx);
+		Interface(Usb_device &device, uint8_t idx, uint8_t alt = 0);
 
 		void handle_events();
 	};
@@ -108,9 +108,10 @@ struct Usb_device
 };
 
 
-Usb_device::Interface::Interface(Usb_device &device, uint8_t idx)
+Usb_device::Interface::Interface(Usb_device &device, uint8_t idx, uint8_t alt)
 :
-	Usb::Interface(device._device, Usb::Interface::Index{idx, 0}, (1UL << 20)),
+	Usb::Interface(device._device, Usb::Interface::Index{idx, alt},
+	               (1UL << 20)),
 	Registry<Usb_device::Interface>::Element(device._interfaces, *this),
 	_device(device)
 {
@@ -461,11 +462,21 @@ static int genode_set_interface_altsetting(struct libusb_device_handle* dev_hand
 	    altsetting < 0 || altsetting > 0xff)
 		return LIBUSB_ERROR_INVALID_PARAM;
 
+	/* remove already claimed interface with old setting */
+	device()._interfaces.for_each([&] (Usb_device::Interface &iface) {
+		if (iface.index().number == interface_number)
+			destroy(device()._alloc, &iface); });
+
 	Usb_device::Urb urb(nullptr, 0, device()._device, P::Request::SET_INTERFACE,
 	                    Rt::value(P::Recipient::IFACE, P::Type::STANDARD,
 	                              P::Direction::OUT),
 	                    (uint8_t)altsetting, (uint8_t)interface_number, 0);
 	device()._wait_for_urb(urb);
+
+	/* claim interface */
+	new (device()._alloc)
+		Usb_device::Interface(device(), (uint8_t) interface_number,
+		                      (uint8_t) altsetting);
 	return LIBUSB_SUCCESS;
 }
 
diff --git a/repos/os/include/usb_session/device.h b/repos/os/include/usb_session/device.h
index 412bfcf149..765d819425 100644
--- a/repos/os/include/usb_session/device.h
+++ b/repos/os/include/usb_session/device.h
@@ -671,6 +671,8 @@ inline Usb::Interface::Interface(Device &device, Index idx, size_t buffer_size)
 	device._for_each_iface([&] (Xml_node node) {
 		if (node.attribute_value<uint16_t>("number", INVALID) != idx.number)
 			return;
+		if (node.attribute_value<uint16_t>("alt_setting", INVALID) != idx.alt_setting)
+			return;
 		node.for_each_sub_node("endpoint", [&] (Xml_node node) {
 			Endpoint ep { node.attribute_value<uint8_t>("address", 0),
 			              node.attribute_value<uint8_t>("attributes", 0) };