From: Hans Petter Selasky Date: Fri, 2 Sep 2011 06:17:17 +0000 (+0200) Subject: musb_gadget: Fix for spurious interrupts on endpoint zero. X-Git-Tag: next-20111004~8^2~58 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=de76cc2ba2116322f1bcc26f5b22d6092bb63a0d;p=karo-tx-linux.git musb_gadget: Fix for spurious interrupts on endpoint zero. There is a multi-year old bug in the MUSB hardware which is not documented. It causes spurious interrupts and have various symptoms, like endless "SetupEnd came in a wrong ep0stage" messages. The fix is taken from the FreeBSD's musb driver. How to reproduce: For example issue clear-stall on a couple of endpoints very fast, like one request per 125us. After a while the bug triggers and the musb-chip becomes unusable until next re-enumeration. Signed-off-by: Hans Petter Selasky Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/musb/musb_gadget_ep0.c b/drivers/usb/musb/musb_gadget_ep0.c index 9378b359c1f0..6a0d0467ec74 100644 --- a/drivers/usb/musb/musb_gadget_ep0.c +++ b/drivers/usb/musb/musb_gadget_ep0.c @@ -679,6 +679,14 @@ irqreturn_t musb_g_ep0_irq(struct musb *musb) musb_readb(mbase, MUSB_FADDR), decode_ep0stage(musb->ep0_state)); + if (csr & MUSB_CSR0_P_DATAEND) { + /* + * If DATAEND is set we should not call the callback, + * hence the status stage is not complete. + */ + return IRQ_HANDLED; + } + /* I sent a stall.. need to acknowledge it now.. */ if (csr & MUSB_CSR0_P_SENTSTALL) { musb_writew(regs, MUSB_CSR0,