论坛徽章:: 0

电梯直达

1楼 [收藏(0)] [报告]

发表于 2011-12-22 08:51 |只看该作者 |倒序浏览

Andrew Huang <bluedrum@163.com> 转载请注明作者及联络方式

Linux HID的raw设备结点，是/dev/hidraw0 ,用来与设备作原始的通讯。

操作系统提供了hid-example.c,来演示如何操作

http://www.emdebian.org/~zumbi/kernel/linux-2.6-3.0.0~rc1/samples/hidraw/hid-example.c

从内核的代码来看，/dev/hidraw0只能操作 endpoint 0,即通用的控制通道,强行向其写入数据会提示

write: Broken pipe

不过可以修改修改来修正这个BUG。在内核 2.6.35后进行修正。

http://git.kernel.org/?p=linux/kernel/git/next/linux-next.git;a=blobdiff;f=drivers/hid/usbhid/hid-core.c;h=f9640a362caa956e61ffd16ad105ebd83c96883d;hp=245aef0de8f22e6f04a5a9432d6bb2c3347565bc;hb=a8ab5d58b0238b8199cc699b8dff7c5e1da24138;hpb=117ea33a18392685b92928bbaa4e84dbc5be8f93

或者

https://patchwork.kernel.org/patch/99990/

--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -807,16 +807,36 @@ static int usbhid_output_raw_report(struct hid_device *hid, __u8 *buf, size_t co
        struct usb_host_interface *interface = intf->cur_altsetting;
        int ret;
 
-       ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
-               HID_REQ_SET_REPORT,
-               USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
-               ((report_type + 1) << 8) | *buf,
-               interface->desc.bInterfaceNumber, buf + 1, count - 1,
-               USB_CTRL_SET_TIMEOUT);
-
-       /* count also the report id */
-       if (ret > 0)
-               ret++;
+       if (usbhid->urbout) {
+               int actual_length;
+               int skipped_report_id = 0;
+               if (buf[0] == 0x0) {
+                       /* Don't send the Report ID */
+                       buf++;
+                       count--;
+                       skipped_report_id = 1;
+               }
+               ret = usb_interrupt_msg(dev, usbhid->urbout->pipe,
+                       buf, count, &actual_length,
+                       USB_CTRL_SET_TIMEOUT);
+               /* return the number of bytes transferred */
+               if (ret == 0) {
+                       ret = actual_length;
+                       /* count also the report id */
+                       if (skipped_report_id)
+                               ret++;
+               }
+       } else {
+               ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+                       HID_REQ_SET_REPORT,
+                       USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+                       ((report_type + 1) << 8) | *buf,
+                       interface->desc.bInterfaceNumber, buf + 1, count - 1,
+                       USB_CTRL_SET_TIMEOUT);
+               /* count also the report id */
+               if (ret > 0)
+                       ret++;
+       }
 
        return ret;
 }