From 5cd8c48d95c10f729090c89757727e090719fd83 Mon Sep 17 00:00:00 2001 From: Zhuang Jin Can Date: Fri, 16 May 2014 05:57:57 +0800 Subject: [PATCH] usb: dwc3: gadget: check link trb after free_slot is increased In ISOC transfers, when free_slot points to the last TRB (i.e. Link TRB), and all queued requests meet Missed Interval Isoc error, busy_slot points to trb0. busy_slot->trb0 trb1 ... free_slot->trb31(Link TRB) After end transfer and receiving the XferNotReady event, trb_left is caculated as 1 which is wrong, and no TRB will be primed to the endpoint. The root cause is free_slot is not increased the same way as busy_slot. When busy_slot is increased by one, it checks if points to a link TRB after increasement, but free_slot checks it before increasement. free_slot should behave the same as busy_slot to make the trb_left caculation correct. Reviewed-by: Pratyush Anand Signed-off-by: Zhuang Jin Can Signed-off-by: Jiebing Li Signed-off-by: Felipe Balbi --- drivers/usb/dwc3/gadget.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 9d64dd02c57e..dab7927d1009 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -828,10 +828,6 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep, length, last ? " last" : "", chain ? " chain" : ""); - /* Skip the LINK-TRB on ISOC */ - if (((dep->free_slot & DWC3_TRB_MASK) == DWC3_TRB_NUM - 1) && - usb_endpoint_xfer_isoc(dep->endpoint.desc)) - dep->free_slot++; trb = &dep->trb_pool[dep->free_slot & DWC3_TRB_MASK]; @@ -843,6 +839,10 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep, } dep->free_slot++; + /* Skip the LINK-TRB on ISOC */ + if (((dep->free_slot & DWC3_TRB_MASK) == DWC3_TRB_NUM - 1) && + usb_endpoint_xfer_isoc(dep->endpoint.desc)) + dep->free_slot++; trb->size = DWC3_TRB_SIZE_LENGTH(length); trb->bpl = lower_32_bits(dma); -- 2.20.1