usb串口驱动程序和ATE1 E0

Question

我正在写一个USB串口适配器设备驱动程序。内核是3.17.4。驱动程序工作正常，除了内核在插入适配器时会打开适配器两次并写入一些命令。下面是驱动程序的dump_stack()和write()。

第一个open()和write()。内核写入"ATE1 E0“三次。

<4>[19964.897631] Call Trace:
<4>[19964.897642]  [<ffffffff8173f929>] dump_stack+0x45/0x56
<4>[19964.897649]  [<ffffffffa04aa1ef>] c0087_open+0x2f/0x160    [usb_com_1p_driver]
<4>[19964.897654]  [<ffffffff81744bb2>] ? down_write+0x12/0x40
<4>[19964.897661]  [<ffffffff81566f75>] serial_port_activate+0x65/0x90
<4>[19964.897667]  [<ffffffff8145e864>] ? tty_port_tty_set+0x64/0xa0
<4>[19964.897671]  [<ffffffff8145edf9>] tty_port_open+0x89/0xe0
<4>[19964.897675]  [<ffffffff81567bf3>] serial_open+0x33/0x70
<4>[19964.897679]  [<ffffffff814560eb>] tty_open+0x17b/0x700
<4>[19964.897684]  [<ffffffff8149cf72>] ? kobj_lookup+0x112/0x170
<4>[19964.897690]  [<ffffffff81211017>] chrdev_open+0xb7/0x1a0
<4>[19964.897694]  [<ffffffff81210f60>] ? cdev_put+0x30/0x30
<4>[19964.897698]  [<ffffffff81209832>] do_dentry_open+0x1d2/0x320
<4>[19964.897702]  [<ffffffff81209b61>] finish_open+0x31/0x50
<4>[19964.897706]  [<ffffffff8121cd7c>] do_last+0xc0c/0x11d0
<4>[19964.897710]  [<ffffffff81217bd8>] ? inode_permission+0x18/0x50
<4>[19964.897713]  [<ffffffff812180e9>] ? link_path_walk+0x99/0xee0
<4>[19964.897717]  [<ffffffff8121d40b>] path_openat+0xcb/0x6d0
<4>[19964.897722]  [<ffffffff8121e2ad>] do_filp_open+0x4d/0xc0
<4>[19964.897726]  [<ffffffff812178db>] ? getname_flags+0x4b/0x180
<4>[19964.897731]  [<ffffffff8122b01e>] ? __alloc_fd+0x7e/0x120
<4>[19964.897735]  [<ffffffff8120b61b>] do_sys_open+0x13b/0x250
<4>[19964.897738]  [<ffffffff8120b74e>] SyS_open+0x1e/0x20
<4>[19964.897743]  [<ffffffff81746ae9>] system_call_fastpath+0x16/0x1b


<4>[19965.026562]  [<ffffffff8173f929>] dump_stack+0x45/0x56
<4>[19965.026569]  [<ffffffffa04aa094>] c0087_write+0x24/0x100 [usb_com_1p_driver]
<4>[19965.026575]  [<ffffffff81567890>] serial_write+0x50/0xc0
<4>[19965.026581]  [<ffffffff814584e5>] n_tty_write+0x495/0x560
<4>[19965.026586]  [<ffffffff810c2850>] ? wake_up_state+0x20/0x20
<4>[19965.026590]  [<ffffffff81454a04>] tty_write+0x174/0x300
<4>[19965.026594]  [<ffffffff81458050>] ? process_echoes+0x70/0x70
<4>[19965.026599]  [<ffffffff8120c597>] vfs_write+0xb7/0x1f0
<4>[19965.026603]  [<ffffffff8120d1c5>] SyS_write+0x55/0xd0
<4>[19965.026608]  [<ffffffff81746ae9>] system_call_fastpath+0x16/0x1b

第二个open()和write()。内核写入"7e 0 78 f0 7e“两次。

<4>[19977.011908] Call Trace:
<4>[19977.011918]  [<ffffffff8173f929>] dump_stack+0x45/0x56
<4>[19977.011925]  [<ffffffffa04aa1ef>] c0087_open+0x2f/0x160 [usb_com_1p_driver]
<4>[19977.011930]  [<ffffffff81744bb2>] ? down_write+0x12/0x40
<4>[19977.011936]  [<ffffffff81566f75>] serial_port_activate+0x65/0x90
<4>[19977.011941]  [<ffffffff8145e864>] ? tty_port_tty_set+0x64/0xa0
<4>[19977.011945]  [<ffffffff8145edf9>] tty_port_open+0x89/0xe0
<4>[19977.011949]  [<ffffffff81567bf3>] serial_open+0x33/0x70
<4>[19977.011952]  [<ffffffff814560eb>] tty_open+0x17b/0x700
<4>[19977.011958]  [<ffffffff81211017>] chrdev_open+0xb7/0x1a0
<4>[19977.011961]  [<ffffffff81210f60>] ? cdev_put+0x30/0x30
<4>[19977.011965]  [<ffffffff81209832>] do_dentry_open+0x1d2/0x320
<4>[19977.011968]  [<ffffffff81209b61>] finish_open+0x31/0x50
<4>[19977.011972]  [<ffffffff8121cd7c>] do_last+0xc0c/0x11d0
<4>[19977.011975]  [<ffffffff81217bd8>] ? inode_permission+0x18/0x50
<4>[19977.011979]  [<ffffffff812180e9>] ? link_path_walk+0x99/0xee0
<4>[19977.011983]  [<ffffffff8121d40b>] path_openat+0xcb/0x6d0
<4>[19977.011986]  [<ffffffff81455de0>] ? tty_release+0x4c0/0x650
<4>[19977.011990]  [<ffffffff8121e2ad>] do_filp_open+0x4d/0xc0
<4>[19977.011993]  [<ffffffff812178db>] ? getname_flags+0x4b/0x180
<4>[19977.011998]  [<ffffffff8122b01e>] ? __alloc_fd+0x7e/0x120
<4>[19977.012002]  [<ffffffff8120b61b>] do_sys_open+0x13b/0x250
<4>[19977.012025]  [<ffffffff8120b74e>] SyS_open+0x1e/0x20
<4>[19977.012031]  [<ffffffff81746ae9>] system_call_fastpath+0x16/0x1b



<4>[19977.026758]  [<ffffffff8173f929>] dump_stack+0x45/0x56
<4>[19977.026766]  [<ffffffffa04aa094>] c0087_write+0x24/0x100 [usb_com_1p_driver]
<4>[19977.026772]  [<ffffffff81567890>] serial_write+0x50/0xc0
<4>[19977.026777]  [<ffffffff814584e5>] n_tty_write+0x495/0x560
<4>[19977.026782]  [<ffffffff810c2850>] ? wake_up_state+0x20/0x20
<4>[19977.026786]  [<ffffffff81454a04>] tty_write+0x174/0x300
<4>[19977.026789]  [<ffffffff81458050>] ? process_echoes+0x70/0x70
<4>[19977.026794]  [<ffffffff8120c597>] vfs_write+0xb7/0x1f0
<4>[19977.026797]  [<ffffffff8120d1c5>] SyS_write+0x55/0xd0
<4>[19977.026802]  [<ffffffff81746ae9>] system_call_fastpath+0x16/0x1b

有人知道这里发生了什么吗？

谢谢!

Answer 1

发送这些命令的正是ModemManager。停止ModemManager之后，不再有针对适配器的命令。

Answer 2

在Ubuntu上，下面的命令解决了这个问题：

sudo stop modemmanager

您可以通过以下方式重新启动它：

sudo start modemmanager