[PATCH] USB: print message when device is rejected due to insufficient power (1fbe75e1) · Commits · 戴 / test

2.6.16 introduces USB power budgeting in the Linux kernel, and since then, a fair number of users have observed that some of their devices no longer work in unpowered hubs (this is not a bug, the devices claim that they need more than 100mA). The very least we can do is print an informational message to the kernel log when this happens, otherwise it is not at all clear why the device was not accepted. Signed-off-by:

Daniel Drake <dsd@gentoo.org> Signed-off-by:

Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hub.c

+9 −1

Original line number	Diff line number	Diff line
		@@ -1176,6 +1176,7 @@ static int choose_configuration(struct usb_device *udev)
		{
		int i;
		int num_configs;
		int insufficient_power = 0;
		struct usb_host_config c, best;

		best = NULL;
		@@ -1228,8 +1229,10 @@ static int choose_configuration(struct usb_device *udev)
		*/

		/* Rule out configs that draw too much bus current */
		if (c->desc.bMaxPower * 2 > udev->bus_mA)
		if (c->desc.bMaxPower * 2 > udev->bus_mA) {
		insufficient_power++;
		continue;
		}

		/* If the first config's first interface is COMM/2/0xff
		* (MSFT RNDIS), rule it out unless Linux has host-side
		@@ -1263,6 +1266,11 @@ static int choose_configuration(struct usb_device *udev)
		best = c;
		}

		if (insufficient_power > 0)
		dev_info(&udev->dev, "rejected %d configuration%s "
		"due to insufficient available bus power\n",
		insufficient_power, plural(insufficient_power));

		if (best) {
		i = best->desc.bConfigurationValue;
		dev_info(&udev->dev,

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