tom.leiming@xxxxxxxxx wrote: > From: Ming Lei <tom.leiming@xxxxxxxxx> > > 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@xxxxxxxxx> > Cc: Anand Gadiyar <gadiyar@xxxxxx> > Cc: Mike Frysinger <vapier@xxxxxxxxxx> > Cc: Sergei Shtylyov <sshtylyov@xxxxxxxxxxxxx> > For OMAPs, Acked-by: Anand Gadiyar <gadiyar@xxxxxx> I sent out this patch a while ago [1]. I've tested it on OMAP3 and OMAP4 silicon. It does look like a logic bug to me, but I'd like the Blackfin and Davinci guys to take a look at the code as well. - Anand [1] <http://marc.info/?l=linux-usb&m=127055442703499&w=2> > --- > 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 550b397..e0bd1c1 100644 > --- a/drivers/usb/musb/musb_gadget.c > +++ b/drivers/usb/musb/musb_gadget.c > @@ -506,18 +506,6 @@ 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 > > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
