From 04914233561377fc0369b984c9d19ec1b6ce2845 Mon Sep 17 00:00:00 2001 From: Thinh Nguyen Date: Mon, 7 Nov 2022 16:37:55 -0800 Subject: [PATCH] usb: dwc3: gadget: Reduce TRB IOC settings When the TRB ring is full, the dwc3 driver must make sure that there's at least 1 TRB with Interrupt On Completion (IOC) set to notify of available TRBs. The current logic just sets the TRB's IOC whenever we run out of TRBs, but it doesn't consider that there may be other TRBs with IOC/LST set already. This creates more events and unnecessary delay from interrupt handling. Only forcefully set IOC when we run out of TRBs and none of the TRBs in the TRB ring has had IOC set. Signed-off-by: Thinh Nguyen Link: https://lore.kernel.org/r/72a1fa448eb1201b152e65be7902a5d1c75b9f3a.1667867687.git.Thinh.Nguyen@synopsys.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/dwc3/gadget.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 5fe2d13..ecddb14 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -1463,8 +1463,18 @@ static int dwc3_prepare_trbs_sg(struct dwc3_ep *dep, */ if (num_trbs_left == 1 || (needs_extra_trb && num_trbs_left <= 2 && - sg_dma_len(sg_next(s)) >= length)) - must_interrupt = true; + sg_dma_len(sg_next(s)) >= length)) { + struct dwc3_request *r; + + /* Check if previous requests already set IOC */ + list_for_each_entry(r, &dep->started_list, list) { + if (r != req && !r->request.no_interrupt) + break; + + if (r == req) + must_interrupt = true; + } + } dwc3_prepare_one_trb(dep, req, trb_length, 1, i, false, must_interrupt); -- 2.7.4