12f188f2e5
A race exists when initializing ueagle-atm devices where the generic atm
device may not yet be created before the driver attempts to initialize
it's PHY signal state, which checks whether the atm device has been
created or not. This often causes the sysfs 'carrier' attribute to be
'1' even though no signal has actually been found.
uea_probe
usbatm_usb_probe
driver->bind (uea_bind)
uea_boot
kthread_run(uea_kthread) uea_kthread
usbatm_atm_init uea_start_reset
atm_dev_register UPDATE_ATM_SIGNAL
UPDATE_ATM_SIGNAL checks whether the ATM device has been created and if
not, will not update the PHY signal state. Because of the race that
does not always happen in time, and the PHY signal state remains
ATM_PHY_SIG_FOUND even though no signal exists.
To fix the race, just create the kthread during initialization, and only
after initialization is complete, start the thread that reboots the
device and initializes PHY state.
[ 3030.490931] uea_probe: calling usbatm_usb_probe
[ 3030.490946] ueagle-atm 8-2:1.0: usbatm_usb_probe: trying driver ueagle-atm with vendor=1110, product=9031, ifnum 0
[ 3030.493691] uea_bind: setting usbatm
[ 3030.496932] usb 8-2: [ueagle-atm] using iso mode
[ 3030.497283] ueagle-atm 8-2:1.0: usbatm_usb_probe: using 3021 byte buffer for rx channel 0xffff880125953508
<kthread already started before usbatm_usb_probe() has returned>
[ 3030.497292] usb 8-2: [ueagle-atm] (re)booting started
<UPDATE_ATM_SIGNAL checks whether ATM device has been created yet before setting PHY state>
[ 3030.497298] uea_start_reset: atm dev (null)
<and since it hasn't been created yet PHY state is not set>
[ 3030.497306] ueagle-atm 8-2:1.0: usbatm_usb_probe: using 3392 byte buffer for tx channel 0xffff8801259535b8
[ 3030.497374] usbatm_usb_probe: about to init
[ 3030.497379] usbatm_usb_probe: calling usbatm_atm_init
<atm device finally gets created>
[ 3030.497384] usbatm_atm_init: creating atm device!
Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
||
|---|---|---|
| .. | ||
| atm | ||
| c67x00 | ||
| class | ||
| core | ||
| early | ||
| gadget | ||
| host | ||
| image | ||
| misc | ||
| mon | ||
| musb | ||
| otg | ||
| serial | ||
| storage | ||
| wusbcore | ||
| Kconfig | ||
| Makefile | ||
| README | ||
| usb-skeleton.c | ||
To understand all the Linux-USB framework, you'll use these resources:
* This source code. This is necessarily an evolving work, and
includes kerneldoc that should help you get a current overview.
("make pdfdocs", and then look at "usb.pdf" for host side and
"gadget.pdf" for peripheral side.) Also, Documentation/usb has
more information.
* The USB 2.0 specification (from www.usb.org), with supplements
such as those for USB OTG and the various device classes.
The USB specification has a good overview chapter, and USB
peripherals conform to the widely known "Chapter 9".
* Chip specifications for USB controllers. Examples include
host controllers (on PCs, servers, and more); peripheral
controllers (in devices with Linux firmware, like printers or
cell phones); and hard-wired peripherals like Ethernet adapters.
* Specifications for other protocols implemented by USB peripheral
functions. Some are vendor-specific; others are vendor-neutral
but just standardized outside of the www.usb.org team.
Here is a list of what each subdirectory here is, and what is contained in
them.
core/ - This is for the core USB host code, including the
usbfs files and the hub class driver ("khubd").
host/ - This is for USB host controller drivers. This
includes UHCI, OHCI, EHCI, and others that might
be used with more specialized "embedded" systems.
gadget/ - This is for USB peripheral controller drivers and
the various gadget drivers which talk to them.
Individual USB driver directories. A new driver should be added to the
first subdirectory in the list below that it fits into.
image/ - This is for still image drivers, like scanners or
digital cameras.
../input/ - This is for any driver that uses the input subsystem,
like keyboard, mice, touchscreens, tablets, etc.
../media/ - This is for multimedia drivers, like video cameras,
radios, and any other drivers that talk to the v4l
subsystem.
../net/ - This is for network drivers.
serial/ - This is for USB to serial drivers.
storage/ - This is for USB mass-storage drivers.
class/ - This is for all USB device drivers that do not fit
into any of the above categories, and work for a range
of USB Class specified devices.
misc/ - This is for all USB device drivers that do not fit
into any of the above categories.