From f8fe2735daaf662876d1333075991997c04d5359 Mon Sep 17 00:00:00 2001 From: Anson Jacob Date: Mon, 23 Jun 2014 19:07:44 +0800 Subject: [PATCH] usb: gadget: f_accessory: Enabled Zero Length Packet (ZLP) for acc_write Accessory connected to Android Device requires Zero Length Packet (ZLP) to be written when data transferred out from the Android device are multiples of wMaxPacketSize (64bytes (Full-Speed) / 512bytes (High-Speed)) to end the transfer. Change-Id: Ib2c2c0ab98ef9afa10e74a720142deca5c0ed476 Signed-off-by: Anson Jacob --- drivers/usb/gadget/f_accessory.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/usb/gadget/f_accessory.c b/drivers/usb/gadget/f_accessory.c index 53e50b5e8612..a401acdceb4d 100644 --- a/drivers/usb/gadget/f_accessory.c +++ b/drivers/usb/gadget/f_accessory.c @@ -662,10 +662,17 @@ static ssize_t acc_write(struct file *fp, const char __user *buf, break; } - if (count > BULK_BUFFER_SIZE) + if (count > BULK_BUFFER_SIZE) { xfer = BULK_BUFFER_SIZE; - else + /* ZLP, They will be more TX requests so not yet. */ + req->zero = 0; + } else { xfer = count; + /* If the data length is a multple of the + * maxpacket size then send a zero length packet(ZLP). + */ + req->zero = ((xfer % dev->ep_in->maxpacket) == 0); + } if (copy_from_user(req->buf, buf, xfer)) { r = -EFAULT; break; -- 2.34.1