Hi,
Upon booting 2.6.37 for the first time any open(2) request for the TTY
port of my Pantech UML290 (new Verizon LTE dongle) returned EAGAIN.
(lsusb for the device at the bottom) This did not happen with 2.6.36.
The USB interface in question is #2, the QCDM DIAG port of the device.
The other ports are standard CDC-ACM for minimal AT commands, and
vendor-specific ports for RmNet (Qualcomm pseudo-ethernet protocol),
another proprietary control protocol, and a GPS port.
The callpath below is what I believe is happening to return EAGAIN to
open() of the DIAG tty:
tty_open
tty_init_dev
tty_driver_install_tty
driver->ops->install
serial_install
usb_autopm_get_interface (returns -EAGAIN)
pm_runtime_get_sync
__pm_runtime_resume
rpm_resume
rpm_resume() executes this code:
else if (dev->power.disable_depth > 0)
retval = -EAGAIN;
which I think is the culprit, since not much else below
usb_autopm_get_interface() returns EAGAIN.
Here's /sys/class/tty/ttyUSB0/power:
[dcbw@dcbw power]$ ls
async runtime_active_kids runtime_status wakeup wakeup_count wakeup_max_time_ms
autosuspend_delay_ms runtime_active_time runtime_suspended_time wakeup_active wakeup_hit_count wakeup_total_time_ms
control runtime_enabled runtime_usage wakeup_active_count wakeup_last_time_ms
[dcbw@dcbw power]$ cat runtime_enabled
disabled
[dcbw@dcbw power]$ cat runtime_status
unsupported
which seems to corroborate that disable_depth > 0 for this device. The
hunk in question is from:
1bfee5bc Alan Stern 2010-09-25
Does anyone have ideas how to debug further? Clearly for this device
pm_runtime_enable() isn't getting called, and thus rpm_resume() is
bailing out early. Perhaps the device doesn't actually support
autosuspend or something, but that shouldn't cause open(2) to fail...
Do other USB serial devices that don't support autosuspend work with
2.6.37?
Dan
----------
Bus 002 Device 015: ID 106c:3718 Curitel Communications, Inc.
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 2 Communications
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x106c Curitel Communications, Inc.
idProduct 0x3718
bcdDevice 0.00
iManufacturer 3 Pantech, Incorporated
iProduct 2 PANTECH UML290
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 166
bNumInterfaces 6
bConfigurationValue 1
iConfiguration 1 Pantech, Incorporated
bmAttributes 0xc0
Self Powered
MaxPower 500mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 2 Communications
bInterfaceSubClass 2 Abstract (modem)
bInterfaceProtocol 1 AT-commands (v.25ter)
iInterface 0
CDC Header:
bcdCDC 1.10
CDC ACM:
bmCapabilities 0x02
line coding and serial state
CDC Call Management:
bmCapabilities 0x03
call management
use DataInterface
bDataInterface 1
CDC Union:
bMasterInterface 0
bSlaveInterface 1
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 5
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 10 CDC Data
bInterfaceSubClass 0 Unused
bInterfaceProtocol 0
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 32
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x01 EP 1 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 32
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 2
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x83 EP 3 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 32
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 32
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 3
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 253
bInterfaceProtocol 255
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x84 EP 4 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 32
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x03 EP 3 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 32
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 4
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 254
bInterfaceProtocol 255
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x85 EP 5 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 32
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x04 EP 4 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 32
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 5
bAlternateSetting 0
bNumEndpoints 3
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 240
bInterfaceProtocol 255
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x86 EP 6 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 5
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x87 EP 7 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 32
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x05 EP 5 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0200 1x 512 bytes
bInterval 32
Device Qualifier (for other device speed):
bLength 10
bDescriptorType 6
bcdUSB 2.00
bDeviceClass 2 Communications
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
bNumConfigurations 1
Device Status: 0x0000
(Bus Powered)
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