linux/drivers/usb/core/message.c, branch v3.6

USB: Enable Latency Tolerance Messaging (LTM).

2012-07-11T11:06:48Z

USB 3.0 devices may optionally support a new feature called Latency Tolerance Messaging. If both the xHCI host controller and the device support LTM, it should be turned on in order to give the system hardware a better clue about the latency tolerance values of its PCI devices. Once a Set Feature request to enable LTM is received, the USB 3.0 device will begin to send LTM updates as its buffers fill or empty, and it can tolerate more or less latency. The USB 3.0 spec, section C.4.2 says that LTM should be disabled just before the device is placed into suspend. Then the device will send an updated LTM notification, so that the system doesn't think it should remain in an active state in order to satisfy the latency requirements of the suspended device. The Set and Clear Feature LTM enable command can only be sent to a configured device. The device will respond with an error if that command is sent while it is in the Default or Addressed state. Make sure to check udev->actconfig in usb_enable_ltm() and usb_disable_ltm(), and don't send those commands when the device is unconfigured. LTM should be enabled once a new configuration is installed in usb_set_configuration(). If we end up sending duplicate Set Feature LTM Enable commands on a switch from one installed configuration to another configuration, that should be harmless. Make sure that LTM is disabled before the device is unconfigured in usb_disable_device(). If no drivers are bound to the device, it doesn't make sense to allow the device to control the latency tolerance of the xHCI host controller. Signed-off-by: Sarah Sharp

USB: Fix LPM disable count mismatch on driver unbind.

2012-07-11T11:06:47Z

When a user runs `echo 0 > bConfigurationValue` for a USB 3.0 device, usb_disable_device() is called. This function disables all drivers, deallocates interfaces, and sets the device configuration value to 0 (unconfigured). With the new scheme to ensure that unconfigured devices have LPM disabled, usb_disable_device() must call usb_unlocked_disable_lpm() once it unconfigures the device. This commit should be backported to kernels as old as 3.5, that contain the commit 8306095fd2c1100e8244c09bf560f97aca5a311d "USB: Disable USB 3.0 LPM in critical sections." Signed-off-by: Sarah Sharp Cc: stable@vger.kernel.org

USB: Disable LPM while the device is unconfigured.

2012-07-11T11:06:46Z

The USB 3.0 Set/Clear Feature U1/U2 Enable cannot be sent to a device in the Default or Addressed state. It can only be sent to a configured device. Change the USB core to initialize the LPM disable count to 1 (disabled), which reflects this limitation. Change usb_set_configuration() to ensure that if the device is unconfigured on entry, usb_lpm_disable() is not called. This avoids sending the Clear Feature U1/U2 when the device is in the Addressed state. When usb_set_configuration() exits with a successfully installed configuration, usb_lpm_enable() will be called. Once the new configuration is installed, make sure usb_set_configuration() only calls usb_enable_lpm() if the device moved to the Configured state. If we have unconfigured the device by sending it a Set Configuration for config 0, don't enable LPM. This commit should be backported to kernels as old as 3.5, that contain the commit 8306095fd2c1100e8244c09bf560f97aca5a311d "USB: Disable USB 3.0 LPM in critical sections." Signed-off-by: Sarah Sharp Cc: stable@vger.kernel.org

Merge 3.5-rc3 into usb-next

2012-06-20T23:24:02Z

This lets us catch the USB fixes that went into 3.5-rc3 into this branch, as we want them here as well. Signed-off-by: Greg Kroah-Hartman

USB: fix gathering of interface associations

2012-06-15T00:13:34Z

TEAC's UD-H01 (and probably other devices) have a gap in the interface number allocation of their descriptors: Configuration Descriptor: bLength 9 bDescriptorType 2 wTotalLength 220 bNumInterfaces 3 [...] Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 0 bAlternateSetting 0 [...] Interface Association: bLength 8 bDescriptorType 11 bFirstInterface 2 bInterfaceCount 2 bFunctionClass 1 Audio bFunctionSubClass 0 bFunctionProtocol 32 iFunction 4 Interface Descriptor: bLength 9 bDescriptorType 4 bInterfaceNumber 2 bAlternateSetting 0 [...] Once a configuration is selected, usb_set_configuration() walks the known interfaces of a given configuration and calls find_iad() on each of them to set the interface association pointer the interface is included in. The problem here is that the loop variable is taken for the interface number in the comparison logic that gathers the association. Which is fine as long as the descriptors are sane. In the case above, however, the logic gets out of sync and the interface association fields of all interfaces beyond the interface number gap are wrong. Fix this by passing the interface's bInterfaceNumber to find_iad() instead. Signed-off-by: Daniel Mack Reported-by: bEN Reported-by: Ivan Perrone Tested-by: ivan perrone Cc: stable Signed-off-by: Greg Kroah-Hartman

USB: allow match on bInterfaceNumber

2012-06-13T22:40:09Z

Some composite USB devices provide multiple interfaces with different functions, all using "vendor-specific" for class/subclass/protocol. Another OS use interface numbers to match the driver and interface. It seems these devices are designed with that in mind - using static interface numbers for the different functions. This adds support for matching against the bInterfaceNumber, allowing such devices to be supported without having to resort to testing against interface number whitelists and/or blacklists in the probe. Signed-off-by: Bjørn Mork Signed-off-by: Greg Kroah-Hartman

USB: Disable USB 3.0 LPM in critical sections.

2012-05-18T22:41:59Z

There are several places where the USB core needs to disable USB 3.0 Link PM: - usb_bind_interface - usb_unbind_interface - usb_driver_claim_interface - usb_port_suspend/usb_port_resume - usb_reset_and_verify_device - usb_set_interface - usb_reset_configuration - usb_set_configuration Use the new LPM disable/enable functions to temporarily disable LPM around these critical sections. We need to protect the critical section around binding and unbinding USB interface drivers. USB drivers may want to disable hub-initiated USB 3.0 LPM, which will change the value of the U1/U2 timeouts that the xHCI driver will install. We need to disable LPM completely until the driver is bound to the interface, and the driver has a chance to enable whatever alternate interface setting it needs in its probe routine. Then re-enable USB3 LPM, and recalculate the U1/U2 timeout values. We also need to disable LPM in usb_driver_claim_interface, because drivers like usbfs can bind to an interface through that function. Note, there is no way currently for userspace drivers to disable hub-initiated USB 3.0 LPM. Revisit this later. When a driver is unbound, the U1/U2 timeouts may change because we are unbinding the last driver that needed hub-initiated USB 3.0 LPM to be disabled. USB LPM must be disabled when a USB device is going to be suspended. The USB 3.0 spec does not define a state transition from U1 or U2 into U3, so we need to bring the device into U0 by disabling LPM before we can place it into U3. Therefore, call usb_unlocked_disable_lpm() in usb_port_suspend(), and call usb_unlocked_enable_lpm() in usb_port_resume(). If the port suspend fails, make sure to re-enable LPM by calling usb_unlocked_enable_lpm(), since usb_port_resume() will not be called on a failed port suspend. USB 3.0 devices lose their USB 3.0 LPM settings (including whether USB device-initiated LPM is enabled) across device suspend. Therefore, disable LPM before the device will be reset in usb_reset_and_verify_device(), and re-enable LPM after the reset is complete and the configuration/alt settings are re-installed. The calculated U1/U2 timeout values are heavily dependent on what USB device endpoints are currently enabled. When any of the enabled endpoints on the device might change, due to a new configuration, or new alternate interface setting, we need to first disable USB 3.0 LPM, add or delete endpoints from the xHCI schedule, install the new interfaces and alt settings, and then re-enable LPM. Do this in usb_set_interface, usb_reset_configuration, and usb_set_configuration. Basically, there is a call to disable and then enable LPM in all functions that lock the bandwidth_mutex. One exception is usb_disable_device, because the device is disconnecting or otherwise going away, and we should not care about whether USB 3.0 LPM is enabled. Signed-off-by: Sarah Sharp

USB: fix deadlock in bConfigurationValue attribute method

2012-04-17T22:54:57Z

This patch (as154) fixes a self-deadlock that occurs when userspace writes to the bConfigurationValue sysfs attribute for a hub with children. The task tries to lock the bandwidth_mutex at a time when it already owns the lock: The attribute's method calls usb_set_configuration(), which calls usb_disable_device() with the bandwidth_mutex held. usb_disable_device() unregisters the existing interfaces, which causes the hub driver to be unbound. The hub_disconnect() routine calls hub_quiesce(), which calls usb_disconnect() for each of the hub's children. usb_disconnect() attempts to acquire the bandwidth_mutex around a call to usb_disable_device(). The solution is to make usb_disable_device() acquire the mutex for itself instead of requiring the caller to hold it. Then the mutex can cover only the bandwidth deallocation operation and not the region where the interfaces are unregistered. This has the potential to change system behavior slightly when a config change races with another config or altsetting change. Some of the bandwidth released from the old config might get claimed by the other config or altsetting, make it impossible to restore the old config in case of a failure. But since we don't try to recover from config-change failures anyway, this doesn't matter. [This should be marked for stable kernels that contain the commit fccf4e86200b8f5edd9a65da26f150e32ba79808 "USB: Free bandwidth when usb_disable_device is called." That commit was marked for stable kernels as old as 2.6.32.] Signed-off-by: Alan Stern Signed-off-by: Sarah Sharp Cc: stable Signed-off-by: Greg Kroah-Hartman

USB: don't clear urb->dev in scatter-gather library

2012-04-06T20:54:00Z

This patch (as1517b) fixes an error in the USB scatter-gather library. The library code uses urb->dev to determine whether or nor an URB is currently active; the completion handler sets urb->dev to NULL. However the core unlinking routines need to use urb->dev. Since unlinking always racing with completion, the completion handler must not clear urb->dev -- it can lead to invalid memory accesses when a transfer has to be cancelled. This patch fixes the problem by getting rid of the lines that clear urb->dev after urb has been submitted. As a result we may end up trying to unlink an URB that failed in submission or that has already completed, so an extra check is added after each unlink to avoid printing an error message when this happens. The checks are updated in both sg_complete() and sg_cancel(), and the second is updated to match the first (currently it prints out unnecessary warning messages if a device is unplugged while a transfer is in progress). Signed-off-by: Alan Stern Reported-and-tested-by: Illia Zaitsev CC: Ming Lei CC: Signed-off-by: Greg Kroah-Hartman

USB: message: cleanup min_t() cast in usb_sg_init()

2011-09-29T20:13:07Z

"length" is type size_t so the cast to unsigned int truncates the upper bytes. This isn't an issue in real life (I've checked the callers) but it's a bit messy. Signed-off-by: Dan Carpenter Signed-off-by: Greg Kroah-Hartman