From 5f2110b07caa1ddbbadc68f1d34e2c60d8c94796 Mon Sep 17 00:00:00 2001 From: Andrey Smirnov Date: Wed, 22 May 2019 00:34:09 -0700 Subject: usb: host: ehci: Add a comment explaing IOC setting for data Add a comment explaining the rationale behinde QT_TOKEN_IOC(req == NULL). Signed-off-by: Andrey Smirnov Signed-off-by: Sascha Hauer --- drivers/usb/host/ehci-hcd.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'drivers/usb') diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index f0d899e82b..a6f497925e 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -362,6 +362,15 @@ ehci_submit_async(struct usb_device *dev, unsigned long pipe, void *buffer, ret = ehci_prepare_qtd(ehci->dev, td, QT_TOKEN_DT(toggle) | + /* + * We only want this qTD to + * generate an interrupt if + * this is a BULK + * request. Otherwise, we'll + * rely on following status + * stage qTD's IOC to notify us + * that transfer is complete + */ QT_TOKEN_IOC(req == NULL) | QT_TOKEN_PID(pid), buffer, length, -- cgit v1.2.3