commit 8e3503051a59bda7323ed16779fac603fb93ff28
author Jerry Zhang <zhangjerry@google.com> Mon Feb 06 22:41:59 2017 +0000
committer android-build-merger <android-build-merger@google.com> Mon Feb 06 22:41:59 2017 +0000
tree a40853b0c74fadeb7e67be80892972d8dd900641
parent f373f0fa4799140ab412bd5f68ecaa36c52c948a
parent 5d5a91c008e9c29d8fa365b92dc0e1fc08ef9c74

Retry allocations in case of ENODEV am: b4f5426604 am: 75bb252863
am: 5d5a91c008

Change-Id: I822915dd40e9c999a3412ee74e5272ff04e0c7d4

media/mtp/MtpFfsHandle.cpp

diff --git a/media/mtp/MtpFfsHandle.cpp b/media/mtp/MtpFfsHandle.cpp
index 5d747c2..1583218 100644
--- a/media/mtp/MtpFfsHandle.cpp
+++ b/media/mtp/MtpFfsHandle.cpp
@@ -62,8 +62,13 @@
 constexpr int USB_FFS_MAX_WRITE = MTP_BUFFER_SIZE;
 constexpr int USB_FFS_MAX_READ = MTP_BUFFER_SIZE;
 
+static_assert(USB_FFS_MAX_WRITE > 0, "Max r/w values must be > 0!");
+static_assert(USB_FFS_MAX_READ > 0, "Max r/w values must be > 0!");
+
 constexpr unsigned int MAX_MTP_FILE_SIZE = 0xFFFFFFFF;
 
+constexpr size_t ENDPOINT_ALLOC_RETRIES = 10;
+
 struct func_desc {
     struct usb_interface_descriptor intf;
     struct usb_endpoint_descriptor_no_audio sink;
@@ -459,19 +464,28 @@
     mMaxWrite = android::base::GetIntProperty("sys.usb.ffs.max_write", USB_FFS_MAX_WRITE);
     mMaxRead = android::base::GetIntProperty("sys.usb.ffs.max_read", USB_FFS_MAX_READ);
 
-    while (mMaxWrite > USB_FFS_MAX_WRITE && mMaxRead > USB_FFS_MAX_READ) {
+    size_t attempts = 0;
+    while (mMaxWrite >= USB_FFS_MAX_WRITE && mMaxRead >= USB_FFS_MAX_READ &&
+            attempts < ENDPOINT_ALLOC_RETRIES) {
         // If larger contiguous chunks of memory aren't available, attempt to try
         // smaller allocations.
         if (ioctl(mBulkIn, FUNCTIONFS_ENDPOINT_ALLOC, static_cast<__u32>(mMaxWrite)) ||
             ioctl(mBulkOut, FUNCTIONFS_ENDPOINT_ALLOC, static_cast<__u32>(mMaxRead))) {
+            if (errno == ENODEV) {
+                // Driver hasn't enabled endpoints yet.
+                std::this_thread::sleep_for(std::chrono::milliseconds(100));
+                attempts += 1;
+                continue;
+            }
             mMaxWrite /= 2;
             mMaxRead /=2;
         } else {
             return 0;
         }
     }
+    // Try to start MtpServer anyway, with the smallest max r/w values
     PLOG(ERROR) << "Functionfs could not allocate any memory!";
-    return -1;
+    return 0;
 }
 
 int MtpFfsHandle::configure(bool usePtp) {

media/mtp/MtpFfsHandle.h

diff --git a/media/mtp/MtpFfsHandle.h b/media/mtp/MtpFfsHandle.h
index 44ff0f3..b4d5a97 100644
--- a/media/mtp/MtpFfsHandle.h
+++ b/media/mtp/MtpFfsHandle.h
@@ -59,6 +59,10 @@
     int sendFile(mtp_file_range mfr);
     int sendEvent(mtp_event me);
 
+    /**
+     * Open ffs endpoints and allocate necessary kernel and user memory.
+     * Will sleep until endpoints are enabled, for up to 1 second.
+     */
     int start();
     void close();