USB: remove short initial timeout for device descriptor fetch (b89ee19a) · Commits · 戴 / test

This patch (as905) removes a micro-optimization from the hub port initialization code. Previously we had been using a short timeout on the first attempt the read the device descriptor; now we will use the standard timeout length. It's not clear that the short timeout ever provided any benefit. And now we know of one case where it actually hurts: The device can't meet the short timeout and then it gets terminally confused. This fixes Bugzilla #8444. Signed-off-by:

Alan Stern <stern@rowland.harvard.edu> Signed-off-by:

Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/core/hub.c

+4 −9

Original line number	Diff line number	Diff line
		@@ -2201,14 +2201,9 @@ hub_port_init (struct usb_hub hub, struct usb_device udev, int port1,
		continue;
		}

		/* Use a short timeout the first time through,
		* so that recalcitrant full-speed devices with
		* 8- or 16-byte ep0-maxpackets won't slow things
		* down tremendously by NAKing the unexpectedly
		* early status stage. Also, retry on all errors;
		* some devices are flakey.
		* 255 is for WUSB devices, we actually need to use 512.
		* WUSB1.0[4.8.1].
		/* Retry on all errors; some devices are flakey.
		* 255 is for WUSB devices, we actually need to use
		* 512 (WUSB1.0[4.8.1]).
		*/
		for (j = 0; j < 3; ++j) {
		buf->bMaxPacketSize0 = 0;
		@@ -2216,7 +2211,7 @@ hub_port_init (struct usb_hub hub, struct usb_device udev, int port1,
		USB_REQ_GET_DESCRIPTOR, USB_DIR_IN,
		USB_DT_DEVICE << 8, 0,
		buf, GET_DESCRIPTOR_BUFSIZE,
		(i ? USB_CTRL_GET_TIMEOUT : 1000));
		USB_CTRL_GET_TIMEOUT);
		switch (buf->bMaxPacketSize0) {
		case 8: case 16: case 32: case 64: case 255:
		if (buf->bDescriptorType ==

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