From eeb1b2a4a9112bcd05d0ce53b99bbd5404abe060 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Mon, 20 Sep 2010 10:32:02 +0300 Subject: [PATCH] usb: musb: gadget: fix bulk IN infinit hangs in double buffer case This patch fixes one infinite hang of bulk IN transfer in double buffer case, the hang can be observed easily by test #6 of usbtest if musb is configured as g_zero and fifo mode 3 is taken to enable double fifo. In fact, the patch only removes the check for non-empty fifo before loading data from new request into fifo since the check is not correct: -in double buffer case, fifo may accommodate more than one packet, even though it has contained one packet already and is non-empty -since last DMA is completed before calling musb_g_tx, it is sure that fifo may accommodate at least one packet Without applying the patch, new requst enqueued from .complte may not have a chance to be loaded into fifo, then will never be completed and cause infinite hangs. With the patch, on my beagle B5, test#6(queued bulk in) can be passed and test result may go beyond 33Mbyte/s if musb is configured as g_zero and fifo mode 3 is taken, follows the test command: #testusb -D DEV_NAME -c 1024 -t 6 -s 32768 -g 8 [1] [1], -source of testusb : tools/usb/testusb.c under linux kernel; Signed-off-by: Ming Lei Acked-by: Anand Gadiyar Cc: David Brownell Cc: Anand Gadiyar Cc: Mike Frysinger Cc: Sergei Shtylyov Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/usb/musb/musb_gadget.c | 12 ------------ 1 file changed, 12 deletions(-) diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c index de0ca90ceb9b..f206c94b8b1c 100644 --- a/drivers/usb/musb/musb_gadget.c +++ b/drivers/usb/musb/musb_gadget.c @@ -504,18 +504,6 @@ void musb_g_tx(struct musb *musb, u8 epnum) /* ... or if not, then complete it. */ musb_g_giveback(musb_ep, request, 0); - /* - * Kickstart next transfer if appropriate; - * the packet that just completed might not - * be transmitted for hours or days. - * REVISIT for double buffering... - * FIXME revisit for stalls too... - */ - musb_ep_select(mbase, epnum); - csr = musb_readw(epio, MUSB_TXCSR); - if (csr & MUSB_TXCSR_FIFONOTEMPTY) - return; - request = musb_ep->desc ? next_request(musb_ep) : NULL; if (!request) { DBG(4, "%s idle now\n",