target/linux/brcm2708/patches-3.10/0093-dwc_otg-Enable-NAK-holdoff-for-control-split-transac.patch

   1 From 3d8a3a5cbcd4d36768cf53e778d8165aefabd5b0 Mon Sep 17 00:00:00 2001
   2 From: P33M <P33M@github.com>
   3 Date: Fri, 20 Sep 2013 16:08:27 +0100
   4 Subject: [PATCH 093/174] dwc_otg: Enable NAK holdoff for control split
   5  transactions
   6
   7 Certain low-speed devices take a very long time to complete a
   8 data or status stage of a control transaction, producing NAK
   9 responses until they complete internal processing - the USB2.0
  10 spec limit is up to 500mS. This causes the same type of interrupt
  11 storm as seen with USB-serial dongles prior to c8edb238.
  12
  13 In certain circumstances, usually while booting, this interrupt
  14 storm could cause SD card timeouts.
  15 ---
  16  drivers/usb/host/dwc_otg/dwc_otg_hcd_intr.c | 3 +--
  17  1 file changed, 1 insertion(+), 2 deletions(-)
  18
  19 --- a/drivers/usb/host/dwc_otg/dwc_otg_hcd_intr.c
  20 +++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd_intr.c
  21 @@ -1857,8 +1857,7 @@ static int32_t handle_hc_nak_intr(dwc_ot
  22          */
  23         switch(dwc_otg_hcd_get_pipe_type(&qtd->urb->pipe_info)) {
  24                 case UE_BULK:
  25 -               //case UE_INTERRUPT:
  26 -               //case UE_CONTROL:
  27 +               case UE_CONTROL:
  28                 if (nak_holdoff_enable)
  29                         hc->qh->nak_frame = dwc_otg_hcd_get_frame_number(hcd);
  30         }