From 8add17cf8e4c55c8c4342ed42c8cdc1649ce0ab8 Mon Sep 17 00:00:00 2001 From: Douglas Anderson Date: Thu, 28 Jan 2016 18:20:00 -0800 Subject: [PATCH] usb: dwc2: host: Giveback URB in tasklet context In commit 94dfd7edfd5c ("USB: HCD: support giveback of URB in tasklet context") support was added to give back the URB in tasklet context. Let's take advantage of this in dwc2. This speeds up the dwc2 interrupt handler considerably. Note that this requires the change ("usb: dwc2: host: Add a delay before releasing periodic bandwidth") to come first. Note that, as per Alan Stern in , we also need to make sure that the extra delay before the device drivers submit more data doesn't break the scheduler. At the moment the scheduler is pretty broken (see future patches) so it's hard to be 100% certain, but I have yet to see any new breakage introduced by this delay. ...and speeding up interrupt processing for dwc2 is a huge deal because it means we've got a better chance of not missing SOF interrupts. That means we've got an overall win here. Note that when playing USB audio and using a USB webcam and having several USB keyboards plugged in, the crackling on the USB audio device is noticably reduced with this patch. Acked-by: John Youn Signed-off-by: Douglas Anderson Tested-by: Heiko Stuebner Tested-by: Stefan Wahren Signed-off-by: Felipe Balbi --- drivers/usb/dwc2/hcd.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c index 0b6ebc7..4055847 100644 --- a/drivers/usb/dwc2/hcd.c +++ b/drivers/usb/dwc2/hcd.c @@ -2341,9 +2341,7 @@ void dwc2_host_complete(struct dwc2_hsotg *hsotg, struct dwc2_qtd *qtd, kfree(qtd->urb); qtd->urb = NULL; - spin_unlock(&hsotg->lock); usb_hcd_giveback_urb(dwc2_hsotg_to_hcd(hsotg), urb, status); - spin_lock(&hsotg->lock); } /* @@ -2964,7 +2962,7 @@ static struct hc_driver dwc2_hc_driver = { .hcd_priv_size = sizeof(struct wrapper_priv_data), .irq = _dwc2_hcd_irq, - .flags = HCD_MEMORY | HCD_USB2, + .flags = HCD_MEMORY | HCD_USB2 | HCD_BH, .start = _dwc2_hcd_start, .stop = _dwc2_hcd_stop, -- 2.7.4