From 801048c6eac1b3929576689471fb7d965c90268e Mon Sep 17 00:00:00 2001
From: Josh Gao <jmgao@google.com>
Date: Wed, 6 Dec 2017 15:06:14 -0800
Subject: [PATCH] adb: disable USB packet overflow checking on OS X.

OS X appears to be misreporting the maximum packet size on some
hardware. Disable this on OS X until we figure out what's going on.

Bug: http://b/65063965
Bug: https://issuetracker.google.com/70244520
Test: python test_device.py on linux with CHECK_PACKET_OVERFLOW disabled
Test: python test_device.py on darwin (but on hardware that wasn't reproducing this)
Change-Id: I57e1adfa162e40ed79f71f97af552b3f0519324e
---
 adb/client/usb_osx.cpp |  1 +
 adb/transport_usb.cpp  | 14 ++++++++++++++
 2 files changed, 15 insertions(+)

diff --git a/adb/client/usb_osx.cpp b/adb/client/usb_osx.cpp
index 2e999eef3..b15d28a27 100644
--- a/adb/client/usb_osx.cpp
+++ b/adb/client/usb_osx.cpp
@@ -305,6 +305,7 @@ AndroidInterfaceAdded(io_iterator_t iterator)
         handle->devpath = devpath;
         usb_handle* handle_p = handle.get();
         VLOG(USB) << "Add usb device " << serial;
+        LOG(INFO) << "reported max packet size for " << serial << " is " << handle->max_packet_size;
         AddDevice(std::move(handle));
         register_usb_transport(reinterpret_cast<::usb_handle*>(handle_p), serial, devpath.c_str(),
                                1);
diff --git a/adb/transport_usb.cpp b/adb/transport_usb.cpp
index fdecccfc3..a00ed5e4d 100644
--- a/adb/transport_usb.cpp
+++ b/adb/transport_usb.cpp
@@ -27,11 +27,18 @@
 
 #if ADB_HOST
 
+#if defined(__APPLE__)
+#define CHECK_PACKET_OVERFLOW 0
+#else
+#define CHECK_PACKET_OVERFLOW 1
+#endif
+
 // Call usb_read using a buffer having a multiple of usb_get_max_packet_size() bytes
 // to avoid overflow. See http://libusb.sourceforge.net/api-1.0/packetoverflow.html.
 static int UsbReadMessage(usb_handle* h, amessage* msg) {
     D("UsbReadMessage");
 
+#if CHECK_PACKET_OVERFLOW
     size_t usb_packet_size = usb_get_max_packet_size(h);
     CHECK_GE(usb_packet_size, sizeof(*msg));
     CHECK_LT(usb_packet_size, 4096ULL);
@@ -44,6 +51,9 @@ static int UsbReadMessage(usb_handle* h, amessage* msg) {
     }
     memcpy(msg, buffer, sizeof(*msg));
     return n;
+#else
+    return usb_read(h, msg, sizeof(*msg));
+#endif
 }
 
 // Call usb_read using a buffer having a multiple of usb_get_max_packet_size() bytes
@@ -51,6 +61,7 @@ static int UsbReadMessage(usb_handle* h, amessage* msg) {
 static int UsbReadPayload(usb_handle* h, apacket* p) {
     D("UsbReadPayload(%d)", p->msg.data_length);
 
+#if CHECK_PACKET_OVERFLOW
     size_t usb_packet_size = usb_get_max_packet_size(h);
     CHECK_EQ(0ULL, sizeof(p->data) % usb_packet_size);
 
@@ -64,6 +75,9 @@ static int UsbReadPayload(usb_handle* h, apacket* p) {
     }
     CHECK_LE(len, sizeof(p->data));
     return usb_read(h, &p->data, len);
+#else
+    return usb_read(h, &p->data, p->msg.data_length);
+#endif
 }
 
 static int remote_read(apacket* p, atransport* t) {