Attachment 46389 Details for Bug 100533

[patch] Potential patch for this issue.

timings.patch (text/plain), 4.17 KB, created by Greg Kroah-Hartman on 2005-08-18 04:05:40 UTC

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Creator: Greg Kroah-Hartman

Created: 2005-08-18 04:05:40 UTC

Size: 4.17 KB

patch

obsolete

>This is an experimental patch to see if various things may help
>get rid of some intermittent hardware-specific enumeration problems
>we've been seeing over the last year, after various usbcore updates
>to the enumeration code.
>
>Some changes relax some timings, on the notion that maybe not
>all devices obey the specs:
>
>  - Wait a minimum of 200 msec after powering up a hub's ports
>    before expecting them to behave.
>
>  - Wait extra time after port reset before we expect the device
>    to behave ... 10msec isn't all that much to some hardware,
>    so make it 50 msec.
>
>Other changes make the enumeration code more lenient:
>
>  - Only interrogate full speed devices about ep0 maxpacket size.
>
>  - Once we know the ep0 maxpacket size we're using, don't bother
>    trying to read it again.
>
>  - After a set_address() error, reset the port.  Failures in that
>    request leave the device's address indeterminate.
>
>This is EXPERIMENTAL and has only been compile-tested.  Post results
>to linux-usb-devel.
>
>
>--- g26.orig/drivers/usb/core/hub.c	2005-08-11 20:49:11.000000000 -0700
>+++ g26/drivers/usb/core/hub.c	2005-08-17 13:16:12.000000000 -0700
>@@ -435,6 +435,7 @@ void usb_hub_tt_clear_buffer (struct usb
> static void hub_power_on(struct usb_hub *hub)
> {
> 	int port1;
>+	unsigned pgood_delay = hub->descriptor->bPwrOn2PwrGood * 2;
> 
> 	/* if hub supports power switching, enable power on each port */
> 	if ((hub->descriptor->wHubCharacteristics & HUB_CHAR_LPSM) < 2) {
>@@ -444,8 +445,8 @@ static void hub_power_on(struct usb_hub 
> 					USB_PORT_FEAT_POWER);
> 	}
> 
>-	/* Wait for power to be enabled */
>-	msleep(hub->descriptor->bPwrOn2PwrGood * 2);
>+	/* Wait 200+ msec for power to be enabled */
>+	msleep(max(pgood_delay, (unsigned) 200));
> }
> 
> static void hub_quiesce(struct usb_hub *hub)
>@@ -1401,8 +1402,8 @@ static int hub_port_reset(struct usb_hub
> 		/* return on disconnect or reset */
> 		switch (status) {
> 		case 0:
>-			/* TRSTRCY = 10 ms */
>-			msleep(10);
>+			/* TRSTRCY = 10 ms; plus some extra */
>+			msleep(10 + 40);
> 			/* FALL THROUGH */
> 		case -ENOTCONN:
> 		case -ENODEV:
>@@ -2153,6 +2154,7 @@ hub_port_init (struct usb_hub *hub, stru
> 	 */
> 	switch (udev->speed) {
> 	case USB_SPEED_HIGH:		/* fixed at 64 */
>+		udev->descriptor.bMaxPacketSize0 =
> 		udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(64);
> 		break;
> 	case USB_SPEED_FULL:		/* 8, 16, 32, or 64 */
>@@ -2163,6 +2165,7 @@ hub_port_init (struct usb_hub *hub, stru
> 		udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(64);
> 		break;
> 	case USB_SPEED_LOW:		/* fixed at 8 */
>+		udev->descriptor.bMaxPacketSize0 =
> 		udev->ep0.desc.wMaxPacketSize = __constant_cpu_to_le16(8);
> 		break;
> 	default:
>@@ -2193,7 +2196,7 @@ hub_port_init (struct usb_hub *hub, stru
>  
> 	/* Why interleave GET_DESCRIPTOR and SET_ADDRESS this way?
> 	 * Because device hardware and firmware is sometimes buggy in
>-	 * this area, and this is how Linux has done it for ages.
>+	 * this area.
> 	 * Change it cautiously.
> 	 *
> 	 * NOTE:  If USE_NEW_SCHEME() is true we will start by issuing
>@@ -2204,7 +2207,8 @@ hub_port_init (struct usb_hub *hub, stru
> 	 * value.
> 	 */
> 	for (i = 0; i < GET_DESCRIPTOR_TRIES; (++i, msleep(100))) {
>-		if (USE_NEW_SCHEME(retry_counter)) {
>+		if (USE_NEW_SCHEME(retry_counter)
>+				&& !udev->descriptor.bMaxPacketSize0) {
> 			struct usb_device_descriptor *buf;
> 			int r = 0;
> 
>@@ -2268,22 +2272,28 @@ hub_port_init (struct usb_hub *hub, stru
> #undef GET_DESCRIPTOR_BUFSIZE
> 		}
> 
>+		/* after set_address errors it's not clear what the
>+		 * device's address will be; so reset, and be sure.
>+		 */
> 		for (j = 0; j < SET_ADDRESS_TRIES; ++j) {
> 			retval = hub_set_address(udev);
> 			if (retval >= 0)
> 				break;
>-			msleep(200);
>+			(void) hub_port_reset(hub, port1, udev, delay);
> 		}
> 		if (retval < 0) {
> 			dev_err(&udev->dev,
> 				"device not accepting address %d, error %d\n",
> 				udev->devnum, retval);
>-			goto fail;
>+			continue;
> 		}
>+
>+		/* don't expect hardware to jump through needless hoops */
>+		if (udev->descriptor.bMaxPacketSize0)
>+			break;
>  
> 		/* cope with hardware quirkiness:
> 		 *  - let SET_ADDRESS settle, some device hardware wants it
>-		 *  - read ep0 maxpacket even for high and low speed,
>   		 */
> 		msleep(10);
> 		if (USE_NEW_SCHEME(retry_counter))

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Attachments on bug 100533: 46389