From 1ae7aca2d3a283cf75f1cdf2df404ecb97423236 Mon Sep 17 00:00:00 2001
From: Gerd Hoffmann <kraxel@redhat.com>
Date: Mon, 3 Jun 2019 13:45:50 +0200
Subject: [PATCH 7/9] usb-host: avoid libusb_set_configuration calls
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RH-Author: Gerd Hoffmann <kraxel@redhat.com>
Message-id: <20190603134550.30153-5-kraxel@redhat.com>
Patchwork-id: 88450
O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH 4/4] usb-host: avoid libusb_set_configuration calls
Bugzilla: 1710861
RH-Acked-by: Philippe Mathieu-Daudé <philmd@redhat.com>
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
RH-Acked-by: Max Reitz <mreitz@redhat.com>
RH-Acked-by: Miroslav Rezanina <mrezanin@redhat.com>

Seems some devices become confused when we call
libusb_set_configuration().  So before calling the function check
whenever the device has multiple configurations in the first place, and
in case it hasn't (which is the case for the majority of devices) simply
skip the call as it will have no effect anyway.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Message-id: 20190522094702.17619-4-kraxel@redhat.com
(cherry picked from commit bfe44898848614cfcb3a269bc965afbe1f0f331c)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/usb/host-libusb.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/hw/usb/host-libusb.c b/hw/usb/host-libusb.c
index 1d7e386..878c515 100644
--- a/hw/usb/host-libusb.c
+++ b/hw/usb/host-libusb.c
@@ -1216,19 +1216,21 @@ static void usb_host_set_address(USBHostDevice *s, int addr)
 
 static void usb_host_set_config(USBHostDevice *s, int config, USBPacket *p)
 {
-    int rc;
+    int rc = 0;
 
     trace_usb_host_set_config(s->bus_num, s->addr, config);
 
     usb_host_release_interfaces(s);
-    rc = libusb_set_configuration(s->dh, config);
-    if (rc != 0) {
-        usb_host_libusb_error("libusb_set_configuration", rc);
-        p->status = USB_RET_STALL;
-        if (rc == LIBUSB_ERROR_NO_DEVICE) {
-            usb_host_nodev(s);
+    if (s->ddesc.bNumConfigurations != 1) {
+        rc = libusb_set_configuration(s->dh, config);
+        if (rc != 0) {
+            usb_host_libusb_error("libusb_set_configuration", rc);
+            p->status = USB_RET_STALL;
+            if (rc == LIBUSB_ERROR_NO_DEVICE) {
+                usb_host_nodev(s);
+            }
+            return;
         }
-        return;
     }
     p->status = usb_host_claim_interfaces(s, config);
     if (p->status != USB_RET_SUCCESS) {
-- 
1.8.3.1