patch "usb: gadget: core: Fix ->udc_set_speed() speed handling" added to usb-linus

patch "usb: gadget: core: Fix ->udc_set_speed() speed handling" added to usb-linus

[gregkh]

This is a note to let you know that I've just added the patch titled

    usb: gadget: core: Fix ->udc_set_speed() speed handling

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From a4f0927ef588cf62bb864707261482c874352942 Mon Sep 17 00:00:00 2001
From: Roger Quadros <rogerq@ti.com>
Date: Tue, 31 Oct 2017 15:56:29 +0200
Subject: usb: gadget: core: Fix ->udc_set_speed() speed handling

Currently UDC core calls ->udc_set_speed() with the speed parameter
containing the maximum speed supported by the gadget function
driver. This might very well be more than that supported by the
UDC controller driver.

Select the lesser of the 2 speeds so both UDC and gadget function
driver are operating within limits.

This fixes PHY Erratic errors and 2 second enumeration delay on
TI's AM437x platforms.

Fixes: 6099eca796ae ("usb: gadget: core: introduce ->udc_set_speed() method")
Cc: <stable@vger.kernel.org> # v4.13+
Reported-by: Dylan Howey <Dylan.Howey@tennantco.com>
Signed-off-by: Roger Quadros <rogerq@ti.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
---
 drivers/usb/gadget/udc/core.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c
index 61422d624ad0..93eff7dec2f5 100644
--- a/drivers/usb/gadget/udc/core.c
+++ b/drivers/usb/gadget/udc/core.c
@@ -1069,8 +1069,12 @@ static inline void usb_gadget_udc_stop(struct usb_udc *udc)
 static inline void usb_gadget_udc_set_speed(struct usb_udc *udc,
 					    enum usb_device_speed speed)
 {
-	if (udc->gadget->ops->udc_set_speed)
-		udc->gadget->ops->udc_set_speed(udc->gadget, speed);
+	if (udc->gadget->ops->udc_set_speed) {
+		enum usb_device_speed s;
+
+		s = min(speed, udc->gadget->max_speed);
+		udc->gadget->ops->udc_set_speed(udc->gadget, s);
+	}
 }
 
 /**
-- 
2.15.1