diff options
Diffstat (limited to 'usb/usb-fix-issue-with-usb-3.0-devices-after-system-resume.patch')
| -rw-r--r-- | usb/usb-fix-issue-with-usb-3.0-devices-after-system-resume.patch | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/usb/usb-fix-issue-with-usb-3.0-devices-after-system-resume.patch b/usb/usb-fix-issue-with-usb-3.0-devices-after-system-resume.patch new file mode 100644 index 00000000000000..59451e9ac658ae --- /dev/null +++ b/usb/usb-fix-issue-with-usb-3.0-devices-after-system-resume.patch @@ -0,0 +1,97 @@ +From sarah.a.sharp@linux.intel.com Thu Oct 14 11:49:31 2010 +Date: Thu, 14 Oct 2010 07:22:54 -0700 +From: Sarah Sharp <sarah.a.sharp@linux.intel.com> +To: Greg KH <gregkh@suse.de> +Cc: linux-usb@vger.kernel.org, "He, Alex" <Alex.He@amd.com>, + "Su, Henry" <Henry.Su@amd.com>, Andiry Xu <andiry.xu@amd.com> +Subject: usb: Fix issue with USB 3.0 devices after system resume +Message-ID: <20101014142254.GA2928@xanatos> +Content-Disposition: inline + +From: Sarah Sharp <sarah.a.sharp@linux.intel.com> + +When the system suspends and a host controller's power is lost, the USB +core attempts to revive any USB devices that had the persist_enabled flag +set. For non-SuperSpeed devices, it will disable the port, and then set +the udev->reset_resume flag. This will cause the USB core to reset the +device, verify the device descriptors to make sure it's the same device, +and re-install any non-default configurations or alternate interface +settings. + +However, we can't disable SuperSpeed root hub ports because that turns off +SuperSpeed terminations, which will inhibit any devices connecting at USB +3.0 speeds. (Plus external hubs don't allow SuperSpeed ports to be +disabled.) + +Because of this logic in hub_activate(): + /* We can forget about a "removed" device when there's a + * physical disconnect or the connect status changes. + */ + if (!(portstatus & USB_PORT_STAT_CONNECTION) || + (portchange & USB_PORT_STAT_C_CONNECTION)) + clear_bit(port1, hub->removed_bits); + + if (!udev || udev->state == USB_STATE_NOTATTACHED) { + /* Tell khubd to disconnect the device or + * check for a new connection + */ + if (udev || (portstatus & USB_PORT_STAT_CONNECTION)) + set_bit(port1, hub->change_bits); + + } else if (portstatus & USB_PORT_STAT_ENABLE) { + /* The power session apparently survived the resume. + * If there was an overcurrent or suspend change + * (i.e., remote wakeup request), have khubd + * take care of it. + */ + if (portchange) + set_bit(port1, hub->change_bits); + + } else if (udev->persist_enabled) { + udev->reset_resume = 1; + set_bit(port1, hub->change_bits); + + } else { + /* The power session is gone; tell khubd */ + usb_set_device_state(udev, USB_STATE_NOTATTACHED); + set_bit(port1, hub->change_bits); + } + +a SuperSpeed device after a resume with a loss of power will never get the +reset_resume flag set. Instead the core will assume the power session +survived and that the device still has the same address, configuration, +and alternate interface settings. The xHCI host controller will have no +knowledge of the device (since all xhci_virt_devices were destroyed when +power loss was discovered, and xhci_discover_or_reset_device() has not +been called), and all URBs to the device will fail. + +If the device driver responds by resetting the device, everything will +continue smoothly. However, if lsusb is used before the device driver +resets the device (or there is no driver), then all lsusb descriptor +fetches will fail. + +The quick fix is to pretend the port is disabled in hub_activate(), by +clearing the local variable. But I'm not sure what other parts of the hub +driver need to be changed because they have assumptions about when ports +will be disabled. + +Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> +Signed-off-by: Andiry Xu <andiry.xu@amd.com> +Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> + +--- + drivers/usb/core/hub.c | 3 +++ + 1 file changed, 3 insertions(+) + +--- a/drivers/usb/core/hub.c ++++ b/drivers/usb/core/hub.c +@@ -758,6 +758,9 @@ static void hub_activate(struct usb_hub + clear_port_feature(hdev, port1, + USB_PORT_FEAT_ENABLE); + portstatus &= ~USB_PORT_STAT_ENABLE; ++ } else { ++ /* Pretend that power was lost for USB3 devs */ ++ portstatus &= ~USB_PORT_STAT_ENABLE; + } + } + |