Messages in this thread Patch in this message | | | From | tom.leiming@gmail ... | Subject | [RESEND/PATCH 2/6] USB: musb-gadget: fix bulk IN infinite hangs in double buffer case | Date | Tue, 7 Sep 2010 23:23:30 +0800 |
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From: Ming Lei <tom.leiming@gmail.com>
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 <tom.leiming@gmail.com> Acked-by: Anand Gadiyar <gadiyar@ti.com> Cc: David Brownell <dbrownell@users.sourceforge.net> Cc: Felipe Balbi <me@felipebalbi.com> Cc: Anand Gadiyar <gadiyar@ti.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> --- drivers/usb/musb/musb_gadget.c | 12 ------------ 1 files changed, 0 insertions(+), 12 deletions(-)
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c index de0ca90..f206c94 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", -- 1.6.2.5
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