[PATCH] usb: hub: Treat all hubs as self-powered

0001-usb-hub-Treat-all-hubs-as-self-powered.patch

From f7e2c2b19ea87fd300c3732ce7c1eb93cdad03c7 Mon Sep 17 00:00:00 2001
From: Daniel Thompson <daniel.thompson@linaro.org>
Date: Fri, 22 Sep 2017 12:40:08 +0100
Subject: [PATCH] usb: hub: Treat all hubs as self-powered

This works around a board misconfiguration on the poplar by treating
all hubs as self-powered. This effectively disables all the code in the
kernel to prevent hubs from drawing too much power. USB sockets must be
current limited so physical harm is unlikely... but now an overloaded
bus may end up with all devices being reset (rather than than the
"final straw" device not working).

Please do not try to upstream this patch. This patch takes a "hit it
with a big hammer" approach and other kernel developers may point at me
and call me names when they read the code!

Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
---
 drivers/usb/core/hub.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 6e6797d145dd..ce3878651a3d 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -1499,6 +1499,7 @@ static int hub_configure(struct usb_hub *hub,
 			hub->mA_per_port = hdev->bus_mA;
 			hub->limited_power = 1;
 		}
+#if 0
 	} else if ((hubstatus & (1 << USB_DEVICE_SELF_POWERED)) == 0) {
 		int remaining = hdev->bus_mA -
 			hub->descriptor->bHubContrCurrent;
@@ -1513,6 +1514,7 @@ static int hub_configure(struct usb_hub *hub,
 					"to use all downstream ports\n");
 		hub->mA_per_port = unit_load;	/* 7.2.1 */
 
+#endif
 	} else {	/* Self-powered external hub */
 		/* FIXME: What about battery-powered external hubs that
 		 * provide less current per port? */
-- 
2.13.5