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authorAlan Stern <stern@rowland.harvard.edu>2008-09-22 22:43:08 +0400
committerGreg Kroah-Hartman <gregkh@suse.de>2008-09-24 00:58:10 +0400
commit5257d97a219e17abf8188f136e1189da3b3af33c (patch)
tree0fd223387fe974f395ed09b1d7a0f5c356dddd65 /drivers/usb
parentaf747c460b663a4b7795dc3f6897b5506fde6888 (diff)
downloadlinux-5257d97a219e17abf8188f136e1189da3b3af33c.tar.xz
USB: revert recovery from transient errors
This patch (as1135) essentially reverts the major parts of two earlier patches to usbcore, because they ended up causing a regression. Trying to recover from transient communication errors can lead to other problems, because operations that failed during the error period are not always retried. The simplest example is the initial Set-Config request sent after device enumeration; if it gets lost then it will not be retried and the device will remain unconfigured. This patch restores the old behavior in which any port disconnect or port disable causes the entire device structure to be removed, fixing a reported regression. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Tested-by: Frans Pop <elendil@planet.nl> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/core/hub.c39
1 files changed, 17 insertions, 22 deletions
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 6a5cb018383d..d99963873e37 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2683,35 +2683,17 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
USB_PORT_STAT_C_ENABLE);
#endif
- /* Try to use the debounce delay for protection against
- * port-enable changes caused, for example, by EMI.
- */
- if (portchange & (USB_PORT_STAT_C_CONNECTION |
- USB_PORT_STAT_C_ENABLE)) {
- status = hub_port_debounce(hub, port1);
- if (status < 0) {
- if (printk_ratelimit())
- dev_err (hub_dev, "connect-debounce failed, "
- "port %d disabled\n", port1);
- portstatus &= ~USB_PORT_STAT_CONNECTION;
- } else {
- portstatus = status;
- }
- }
-
/* Try to resuscitate an existing device */
udev = hdev->children[port1-1];
if ((portstatus & USB_PORT_STAT_CONNECTION) && udev &&
udev->state != USB_STATE_NOTATTACHED) {
-
usb_lock_device(udev);
if (portstatus & USB_PORT_STAT_ENABLE) {
status = 0; /* Nothing to do */
- } else if (!udev->persist_enabled) {
- status = -ENODEV; /* Mustn't resuscitate */
#ifdef CONFIG_USB_SUSPEND
- } else if (udev->state == USB_STATE_SUSPENDED) {
+ } else if (udev->state == USB_STATE_SUSPENDED &&
+ udev->persist_enabled) {
/* For a suspended device, treat this as a
* remote wakeup event.
*/
@@ -2726,7 +2708,7 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
#endif
} else {
- status = usb_reset_device(udev);
+ status = -ENODEV; /* Don't resuscitate */
}
usb_unlock_device(udev);
@@ -2741,6 +2723,19 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
usb_disconnect(&hdev->children[port1-1]);
clear_bit(port1, hub->change_bits);
+ if (portchange & (USB_PORT_STAT_C_CONNECTION |
+ USB_PORT_STAT_C_ENABLE)) {
+ status = hub_port_debounce(hub, port1);
+ if (status < 0) {
+ if (printk_ratelimit())
+ dev_err(hub_dev, "connect-debounce failed, "
+ "port %d disabled\n", port1);
+ portstatus &= ~USB_PORT_STAT_CONNECTION;
+ } else {
+ portstatus = status;
+ }
+ }
+
/* Return now if debouncing failed or nothing is connected */
if (!(portstatus & USB_PORT_STAT_CONNECTION)) {
@@ -2748,7 +2743,7 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
if ((wHubCharacteristics & HUB_CHAR_LPSM) < 2
&& !(portstatus & (1 << USB_PORT_FEAT_POWER)))
set_port_feature(hdev, port1, USB_PORT_FEAT_POWER);
-
+
if (portstatus & USB_PORT_STAT_ENABLE)
goto done;
return;