Re: [PATCH 2/3] USB/ACPI: Add usb port's acpi power control in the xhci PORT_POWER feature request process.

Lan Tianyu <tianyu.lan@xxxxxxxxx> · Thu, 14 Jun 2012 15:22:42 +0800

On 2012年06月14日 03:30, Greg KH wrote:

On Mon, Jun 11, 2012 at 10:24:33AM +0800, Lan Tianyu wrote:

On our developping machine, bios can provide usb port's  power control via
acpi. This patch is to provide usb port's power control way through setting
or clearing PORT_POWER feature requests. Add two functions usb_acpi_power_manageable()
and usb_acpi_set_power_state(). The first one is used to find whether the
usb port has acpi power resource and the second is to set the power state.
They are invoked in the xhci_hub_control() where clearing or setting PORT_POWER
feature requests are processed.

Signed-off-by: Lan Tianyu<tianyu.lan@xxxxxxxxx>
---
  drivers/usb/core/usb-acpi.c |   28 ++++++++++++++++++++++++++++
  drivers/usb/host/xhci-hub.c |   10 ++++++++++
  include/linux/usb.h         |   10 ++++++++++
  3 files changed, 48 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/core/usb-acpi.c b/drivers/usb/core/usb-acpi.c
index 82c90d0..e95f26f 100644
--- a/drivers/usb/core/usb-acpi.c
+++ b/drivers/usb/core/usb-acpi.c
@@ -19,6 +19,34 @@

  #include "usb.h"

+bool usb_acpi_power_manageable(struct usb_device *hdev, int port1)
+{
+	acpi_handle port_handle;
+
+	port_handle = usb_get_hub_port_acpi_handle(hdev,
+		port1);
+	return port_handle ? acpi_bus_power_manageable(port_handle) : false;


Ick, I _really_ hate the ? : usage in C, please use real if statements
so that everyone can read and understand them easier.  You do that a lot
here, please fix them all.


Ok. But in some places, for example
dev_dbg(&hdev->dev, "The power of hub port %d was set to %s\n",
		port1, enable ? "enable" : "disable");
try to print two result. ?: is more convenient. If I use "if" statement,
that will be
if (enable)
	result = "enable";
else
	result = "disable";
dev_dbg(&hdev->dev, "The power of hub port %d was set to %s\n",
		port1, result);

This just looks a little complex.


+}
+EXPORT_SYMBOL_GPL(usb_acpi_power_manageable);
+
+int usb_acpi_set_power_state(struct usb_device *hdev, int port1, bool enable)
+{
+	acpi_handle port_handle;
+	unsigned char state;
+	int error = -EINVAL;
+
+	port_handle = (acpi_handle)usb_get_hub_port_acpi_handle(hdev,
+		port1);
+	state = enable ? ACPI_STATE_D0 : ACPI_STATE_D3_COLD;
+	error = acpi_bus_set_power(port_handle, state);


You forgot to check port_handle here.

Why not call usb_acpi_power_manageable() to ensure that you can do this?



In my code, usb_acpi_power_manageable() is invoked before 

usb_acpi_set_power_state().

Do you mean I should call usb_acpi_power_manageable() in the 

usb_acpi_set_power_state()?





+	if (!error)
+		dev_dbg(&hdev->dev, "The power of hub port %d was set to %s\n",
+			port1, enable ? "enable" : "disabe");


Why not report the error if debugging as well?


Ok.




+
+	return error;
+}
+EXPORT_SYMBOL_GPL(usb_acpi_set_power_state);
+
  static int usb_acpi_check_port_connect_type(struct usb_device *hdev,
  	acpi_handle handle, int port1)
  {
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 2c55fcf..0ce48b3 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -728,6 +728,11 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,

  			temp = xhci_readl(xhci, port_array[wIndex]);
  			xhci_dbg(xhci, "set port power, actual port %d status  = 0x%x\n", wIndex, temp);
+
+			if (usb_acpi_power_manageable(hcd->self.root_hub,
+					wIndex + 1))


Why +1?  If you have to do this everywhere, then do it only in the
function, so you can be 0 based properly.

Also, minor coding style nit, please rewrite as:
			if (usb_acpi_power_manageable(hcd->self.root_hub,
						      wIndex + 1))
Or even better yet, use a temp variable for the value returned and then
check that, it's clearer and easier to read, right?


Yeah. Thanks for you suggestion. I will do it.


+				usb_acpi_set_power_state(hcd->self.root_hub,
+					wIndex + 1, true);


Same question about +1 here.


  			break;
  		case USB_PORT_FEAT_RESET:
  			temp = (temp | PORT_RESET);
@@ -830,6 +835,11 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
  		case USB_PORT_FEAT_POWER:
  			xhci_writel(xhci, temp&  ~PORT_POWER,
  				port_array[wIndex]);
+
+			if (usb_acpi_power_manageable(hcd->self.root_hub,
+					wIndex + 1))
+				usb_acpi_set_power_state(hcd->self.root_hub,
+					wIndex + 1, false);
  			break;
  		default:
  			goto error;
diff --git a/include/linux/usb.h b/include/linux/usb.h
index feb0a04..92f8898 100644
--- a/include/linux/usb.h
+++ b/include/linux/usb.h
@@ -599,6 +599,16 @@ extern int usb_lock_device_for_reset(struct usb_device *udev,
  extern int usb_reset_device(struct usb_device *dev);
  extern void usb_queue_reset_device(struct usb_interface *dev);

+#ifdef CONFIG_ACPI
+extern int usb_acpi_set_power_state(struct usb_device *hdev, int port,
+	bool enable);
+extern bool usb_acpi_power_manageable(struct usb_device *hdev, int port);
+#else
+static inline int usb_acpi_set_power_state(struct usb_device *hdev, int port,
+	bool enable) { return 0; }
+static inline bool usb_acpi_power_manageable(struct usb_device *hdev, int port)
+	{ return 0; }


is 0 a bool?  :)

Please get the types right.

So careless. Thanks for reminder.


greg k-h


--
Best Regards
Tianyu Lan
linux kernel enabling team
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