From 7802e2dd2c98f20abdf6eede5541e48876446c09 Mon Sep 17 00:00:00 2001
From: Michael Lotz <mmlr@mlotz.ch>
Date: Tue, 7 Jun 2011 18:17:08 +0000
Subject: [PATCH] Get the HID descriptor from the already retrieved
 configuration info instead of always calling the device and requesting it. If
 no HID descriptor is found in the configuration we fall back to retrieving it
 manually and if that fails we fall back to a dummy report descriptor length.
 In the most usual case this will save one unnecessary USB control request.

Incidentally this also fixes the absolute pointing device under VirtualBox. VBox
stalled the retrieval of the HID descriptor. That alone wasn't so problematic as
in this case we just fell back to the dummy report descriptor length which
would've been large enough. But VBox also times out the next request after the
stall, which in this case was the retrieval of the report descriptor, hence no
HIDDevice could be created.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42019 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 .../drivers/input/usb_hid/HIDDevice.cpp       | 68 +++++++++++++------
 1 file changed, 46 insertions(+), 22 deletions(-)

diff --git a/src/add-ons/kernel/drivers/input/usb_hid/HIDDevice.cpp b/src/add-ons/kernel/drivers/input/usb_hid/HIDDevice.cpp
index 6477bcde4d..8028d4d663 100644
--- a/src/add-ons/kernel/drivers/input/usb_hid/HIDDevice.cpp
+++ b/src/add-ons/kernel/drivers/input/usb_hid/HIDDevice.cpp
@@ -60,31 +60,55 @@ HIDDevice::HIDDevice(usb_device device, const usb_configuration_info *config,
 	}
 
 	if (!hasFixedDescriptor) {
-		// conforming device, read HID and report descriptors
-		descriptorLength = sizeof(usb_hid_descriptor);
-		usb_hid_descriptor *hidDescriptor
-			= (usb_hid_descriptor *)malloc(descriptorLength);
-		if (hidDescriptor == NULL) {
-			TRACE_ALWAYS("failed to allocate buffer for hid descriptor\n");
-			fStatus = B_NO_MEMORY;
-			return;
+		// Conforming device, find the HID descriptor and get the report
+		// descriptor from the device.
+		usb_hid_descriptor *hidDescriptor = NULL;
+
+		const usb_interface_info *interfaceInfo
+			= config->interface[interfaceIndex].active;
+		for (size_t i = 0; i < interfaceInfo->generic_count; i++) {
+			const usb_generic_descriptor &generic
+				= interfaceInfo->generic[i]->generic;
+			if (generic.descriptor_type == B_USB_HID_DESCRIPTOR_HID) {
+				hidDescriptor = (usb_hid_descriptor *)&generic;
+				descriptorLength
+					= hidDescriptor->descriptor_info[0].descriptor_length;
+				break;
+			}
 		}
 
-		status_t result = gUSBModule->send_request(device,
-			USB_REQTYPE_INTERFACE_IN | USB_REQTYPE_STANDARD,
-			USB_REQUEST_GET_DESCRIPTOR,
-			B_USB_HID_DESCRIPTOR_HID << 8, interfaceIndex, descriptorLength,
-			hidDescriptor, &descriptorLength);
+		if (hidDescriptor == NULL) {
+			TRACE_ALWAYS("didn't find a HID descriptor in the configuration, "
+				"trying to retrieve manually\n");
 
-		TRACE("get hid descriptor: result: 0x%08lx; length: %lu\n", result,
-			descriptorLength);
-		if (result == B_OK) {
-			descriptorLength
-				= hidDescriptor->descriptor_info[0].descriptor_length;
-		} else
-			descriptorLength = 256; /* XXX */
+			descriptorLength = sizeof(usb_hid_descriptor);
+			hidDescriptor = (usb_hid_descriptor *)malloc(descriptorLength);
+			if (hidDescriptor == NULL) {
+				TRACE_ALWAYS("failed to allocate buffer for hid descriptor\n");
+				fStatus = B_NO_MEMORY;
+				return;
+			}
 
-		free(hidDescriptor);
+			status_t result = gUSBModule->send_request(device,
+				USB_REQTYPE_INTERFACE_IN | USB_REQTYPE_STANDARD,
+				USB_REQUEST_GET_DESCRIPTOR,
+				B_USB_HID_DESCRIPTOR_HID << 8, interfaceIndex, descriptorLength,
+				hidDescriptor, &descriptorLength);
+
+			TRACE("get hid descriptor: result: 0x%08lx; length: %lu\n", result,
+				descriptorLength);
+			if (result == B_OK) {
+				descriptorLength
+					= hidDescriptor->descriptor_info[0].descriptor_length;
+			} else {
+				descriptorLength = 256; /* XXX */
+				TRACE_ALWAYS("failed to get HID descriptor, trying with a "
+					"fallback report descriptor length of %lu\n",
+					descriptorLength);
+			}
+
+			free(hidDescriptor);
+		}
 
 		reportDescriptor = (uint8 *)malloc(descriptorLength);
 		if (reportDescriptor == NULL) {
@@ -93,7 +117,7 @@ HIDDevice::HIDDevice(usb_device device, const usb_configuration_info *config,
 			return;
 		}
 
-		result = gUSBModule->send_request(device,
+		status_t result = gUSBModule->send_request(device,
 			USB_REQTYPE_INTERFACE_IN | USB_REQTYPE_STANDARD,
 			USB_REQUEST_GET_DESCRIPTOR,
 			B_USB_HID_DESCRIPTOR_REPORT << 8, interfaceIndex, descriptorLength,