usb: block suspension of superspeed port while hispeed peer is active
ClearPortFeature(PORT_POWER) on a usb3 port places the port in either a
DSPORT.Powered-off-detect / DSPORT.Powered-off-reset loop, or the
DSPORT.Powered-off state. There is no way to ensure that RX
terminations will persist in this state, so it is possible a device will
degrade to its usb2 connection. Prevent this by blocking power-off of a
usb3 port while its usb2 peer is active, and powering on a usb3 port
before its usb2 peer.
By default the latency between peer power-on events is 0. In order for
the device to not see usb2 active while usb3 is still powering up inject
the hub recommended power_on_good delay. In support of satisfying the
power_on_good delay outside of hub_power_on() refactor the places where
the delay is consumed to call a new hub_power_on_good_delay() helper.
Finally, because this introduces several new checks for whether a port
is_superspeed, cache that disctinction at port creation so that we don't
need to keep looking up the parent hub device.
Acked-by: Alan Stern <stern@rowland.harvard.edu>
[alan]: add a 'superspeed' flag to the port
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 31a492a..e492bca 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -36,11 +36,6 @@
#define USB_VENDOR_GENESYS_LOGIC 0x05e3
#define HUB_QUIRK_CHECK_PORT_AUTOSUSPEND 0x01
-static inline int hub_is_superspeed(struct usb_device *hdev)
-{
- return (hdev->descriptor.bDeviceProtocol == USB_HUB_PR_SS);
-}
-
/* Protect struct usb_device->state and ->children members
* Note: Both are also protected by ->dev.sem, except that ->state can
* change to USB_STATE_NOTATTACHED even when the semaphore isn't held. */
@@ -822,14 +817,9 @@
}
EXPORT_SYMBOL_GPL(usb_hub_clear_tt_buffer);
-/* If do_delay is false, return the number of milliseconds the caller
- * needs to delay.
- */
-static unsigned hub_power_on(struct usb_hub *hub, bool do_delay)
+static void hub_power_on(struct usb_hub *hub, bool do_delay)
{
int port1;
- unsigned pgood_delay = hub->descriptor->bPwrOn2PwrGood * 2;
- unsigned delay;
/* Enable power on each port. Some hubs have reserved values
* of LPSM (> 2) in their descriptors, even though they are
@@ -848,12 +838,8 @@
else
usb_clear_port_feature(hub->hdev, port1,
USB_PORT_FEAT_POWER);
-
- /* Wait at least 100 msec for power to become stable */
- delay = max(pgood_delay, (unsigned) 100);
if (do_delay)
- msleep(delay);
- return delay;
+ msleep(hub_power_on_good_delay(hub));
}
static int hub_hub_status(struct usb_hub *hub,
@@ -1057,7 +1043,9 @@
* for HUB_POST_RESET, but it's easier not to.
*/
if (type == HUB_INIT) {
- delay = hub_power_on(hub, false);
+ unsigned delay = hub_power_on_good_delay(hub);
+
+ hub_power_on(hub, false);
INIT_DELAYED_WORK(&hub->init_work, hub_init_func2);
queue_delayed_work(system_power_efficient_wq,
&hub->init_work,