Don't send short URB packet when sending MtpDataPacket.
When sending a MtpDataPacket to a MTP device, the kernel driver splits
it into multiple URB packets so that the URB packet size does not exceed
the buffer size at the MTP device.
Previously MtpDataPacket sends its header first, then sends the
payload. It means the first URB packet only contains the header of
MtpDataPacket and the URB packet size is smaller than the maximum URB
packet size (short packet). Some MTP devices regard the short packet as
the end of the sequencail URB packets, thus the devices do not accept
the following URB packets that contain the payload.
The MTP spec says if the responder (MTP device) sends the data in a way
where the first pacekt contains only the header, the initiator (MTP
host) must send data in the same way. Otherwise the initiator must not
send a short packet in the sequencial URB packets.
The CL fixes the MTP host implementation so that it remembers how the
MTP device sends data, and uses the same way when sending data
from the host.
Bug: 31165557
Test: Manually invokes MtpDevice#sendObject
Change-Id: Ic76eb4241ed74957414aef2990be08cd77a9f5a9
diff --git a/media/mtp/MtpDataPacket.h b/media/mtp/MtpDataPacket.h
index 6240f28..82e0ee4 100644
--- a/media/mtp/MtpDataPacket.h
+++ b/media/mtp/MtpDataPacket.h
@@ -93,7 +93,6 @@
inline void putEmptyString() { putUInt8(0); }
inline void putEmptyArray() { putUInt32(0); }
-
#ifdef MTP_DEVICE
// fill our buffer with data from the given file descriptor
int read(int fd);
@@ -110,9 +109,15 @@
int readDataWait(struct usb_device *device);
int readDataHeader(struct usb_request *ep);
- int writeDataHeader(struct usb_request *ep, uint32_t length);
- int write(struct usb_request *ep);
- int write(struct usb_request *ep, void* buffer, uint32_t length);
+ // Write a whole data packet with payload to the end point given by a request. |divisionMode|
+ // specifies whether to divide header and payload. See |UrbPacketDivisionMode| for meanings of
+ // each value. Return the number of bytes (including header size) sent to the device on success.
+ // Otherwise -1.
+ int write(struct usb_request *request, UrbPacketDivisionMode divisionMode);
+ // Similar to previous write method but it reads the payload from |fd|. If |size| is larger than
+ // MTP_BUFFER_SIZE, the data will be sent by multiple bulk transfer requests.
+ int write(struct usb_request *request, UrbPacketDivisionMode divisionMode,
+ int fd, size_t size);
#endif
inline bool hasData() const { return mPacketSize > MTP_CONTAINER_HEADER_SIZE; }