On Tuesday, November 13, 2012 04:00:03 PM Lan Tianyu wrote:
> This patch is to add usb port auto power off mechanism.
> When usb device is suspending, usb core will suspend usb port and
> usb port runtime pm callback will clear PORT_POWER feature to
> power off port if all conditions were met.These conditions are
> remote wakeup disable, pm qos NO_POWER_OFF flag clear and persist
> enable. When device is suspended and power off, usb core
> will ignore port's connect and enable change event to keep the device
> not being disconnected. When it resumes, power on port again.
>
> Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
Again, from the PM side:
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
although as far as the USB internals are concerned, I'm far from being an expert. :-)
Thanks,
Rafael
> ---
> drivers/usb/core/hub.c | 76 +++++++++++++++++++++++++++++++++++++++++++++--
> drivers/usb/core/port.c | 1 +
> include/linux/usb.h | 2 ++
> 3 files changed, 76 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index 2cb414e..267e9d7 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -26,6 +26,7 @@
> #include <linux/mutex.h>
> #include <linux/freezer.h>
> #include <linux/random.h>
> +#include <linux/pm_qos.h>
>
> #include <asm/uaccess.h>
> #include <asm/byteorder.h>
> @@ -159,11 +160,14 @@ MODULE_PARM_DESC(use_both_schemes,
> DECLARE_RWSEM(ehci_cf_port_reset_rwsem);
> EXPORT_SYMBOL_GPL(ehci_cf_port_reset_rwsem);
>
> +#define HUB_PORT_RECONNECT_TRIES 20
> +
> #define HUB_DEBOUNCE_TIMEOUT 1500
> #define HUB_DEBOUNCE_STEP 25
> #define HUB_DEBOUNCE_STABLE 100
>
> static int usb_reset_and_verify_device(struct usb_device *udev);
> +static int hub_port_debounce(struct usb_hub *hub, int port1);
>
> static inline char *portspeed(struct usb_hub *hub, int portstatus)
> {
> @@ -855,7 +859,11 @@ static unsigned hub_power_on(struct usb_hub *hub, bool do_delay)
> dev_dbg(hub->intfdev, "trying to enable port power on "
> "non-switchable hub\n");
> for (port1 = 1; port1 <= hub->descriptor->bNbrPorts; port1++)
> - set_port_feature(hub->hdev, port1, USB_PORT_FEAT_POWER);
> + if (hub->ports[port1 - 1]->power_on)
> + set_port_feature(hub->hdev, port1, USB_PORT_FEAT_POWER);
> + else
> + 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);
> @@ -2852,6 +2860,7 @@ EXPORT_SYMBOL_GPL(usb_enable_ltm);
> int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
> {
> struct usb_hub *hub = hdev_to_hub(udev->parent);
> + struct usb_port *port_dev = hub->ports[udev->portnum - 1];
> int port1 = udev->portnum;
> int status;
>
> @@ -2946,6 +2955,19 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
> udev->port_is_suspended = 1;
> msleep(10);
> }
> +
> + /*
> + * Check whether current status is meeting requirement of
> + * usb port power off mechanism
> + */
> + if (!udev->do_remote_wakeup
> + && (dev_pm_qos_flags(&port_dev->dev,
> + PM_QOS_FLAG_NO_POWER_OFF) != PM_QOS_FLAGS_ALL)
> + && udev->persist_enabled
> + && !status)
> + if (!pm_runtime_put_sync(&port_dev->dev))
> + port_dev->power_on = false;
> +
> usb_mark_last_busy(hub->hdev);
> return status;
> }
> @@ -3029,6 +3051,25 @@ static int finish_port_resume(struct usb_device *udev)
> return status;
> }
>
> +static int usb_port_wait_for_connected(struct usb_hub *hub, int port1)
> +{
> + int status, i;
> +
> + for (i = 0; i < HUB_PORT_RECONNECT_TRIES; i++) {
> + status = hub_port_debounce(hub, port1);
> + if (status & USB_PORT_STAT_CONNECTION) {
> + /*
> + * just clear enable-change feature since debounce
> + * has cleared connect-change feature.
> + */
> + clear_port_feature(hub->hdev, port1,
> + USB_PORT_FEAT_C_ENABLE);
> + return 0;
> + }
> + }
> + return -ETIMEDOUT;
> +}
> +
> /*
> * usb_port_resume - re-activate a suspended usb device's upstream port
> * @udev: device to re-activate, not a root hub
> @@ -3066,10 +3107,36 @@ static int finish_port_resume(struct usb_device *udev)
> int usb_port_resume(struct usb_device *udev, pm_message_t msg)
> {
> struct usb_hub *hub = hdev_to_hub(udev->parent);
> + struct usb_port *port_dev = hub->ports[udev->portnum - 1];
> int port1 = udev->portnum;
> int status;
> u16 portchange, portstatus;
>
> +
> + set_bit(port1, hub->busy_bits);
> +
> + if (!port_dev->power_on) {
> + status = pm_runtime_get_sync(&port_dev->dev);
> + if (status) {
> + dev_dbg(&udev->dev, "can't resume usb port, status %d\n",
> + status);
> + return status;
> + }
> +
> + port_dev->power_on = true;
> +
> + /*
> + * Wait for usb hub port to be reconnected in order to make
> + * the resume procedure successful.
> + */
> + status = usb_port_wait_for_connected(hub, port1);
> + if (status < 0) {
> + dev_dbg(&udev->dev, "can't get reconnection after setting port power on, status %d\n",
> + status);
> + return status;
> + }
> + }
> +
> /* Skip the initial Clear-Suspend step for a remote wakeup */
> status = hub_port_status(hub, port1, &portstatus, &portchange);
> if (status == 0 && !port_is_suspended(hub, portstatus))
> @@ -3077,8 +3144,6 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg)
>
> // dev_dbg(hub->intfdev, "resume port %d\n", port1);
>
> - set_bit(port1, hub->busy_bits);
> -
> /* see 7.1.7.7; affects power usage, but not budgeting */
> if (hub_is_superspeed(hub->hdev))
> status = set_port_feature(hub->hdev,
> @@ -4256,6 +4321,11 @@ static void hub_port_connect_change(struct usb_hub *hub, int port1,
> }
> }
>
> + if (!hub->ports[port1 - 1]->power_on) {
> + clear_bit(port1, hub->change_bits);
> + return;
> + }
> +
> /* Disconnect any existing devices under this port */
> if (udev)
> usb_disconnect(&hub->ports[port1 - 1]->child);
> diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
> index 1cda766..b7388fd 100644
> --- a/drivers/usb/core/port.c
> +++ b/drivers/usb/core/port.c
> @@ -99,6 +99,7 @@ int usb_hub_create_port_device(struct device *intfdev,
> {
> int retval;
>
> + port_dev->power_on = true;
> port_dev->portnum = port1;
> port_dev->dev.parent = intfdev;
> port_dev->dev.groups = port_dev_group;
> diff --git a/include/linux/usb.h b/include/linux/usb.h
> index 71510bf..8002640 100644
> --- a/include/linux/usb.h
> +++ b/include/linux/usb.h
> @@ -579,6 +579,7 @@ struct usb_device {
> * @port_owner: port's owner
> * @connect_type: port's connect type
> * @portnum: port index num based one
> + * @power_on: port's power state
> */
> struct usb_port {
> struct usb_device *child;
> @@ -586,6 +587,7 @@ struct usb_port {
> struct dev_state *port_owner;
> enum usb_port_connect_type connect_type;
> u8 portnum;
> + bool power_on;
> };
> #define to_usb_port(_dev) \
> container_of(_dev, struct usb_port, dev)
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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