Messages in this thread | | | Date | Wed, 29 Apr 2009 16:28:35 -0500 | Subject | Re: Class device namespaces | From | Michael Brown <> |
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On Wed, Apr 29, 2009 at 2:10 PM, Kay Sievers <kay.sievers@vrfy.org> wrote: > Udev runs exactly at the time you create the device, and is not > unlikely faster than your polling, at least not predictable slower. > And it will cancel all requests which can not be fulfilled by udev > itself. > > I strongly recommend switching to a different solution, you can not > use the firmware_class interface on any udev system, the interface is > already taken, and it's a single-user interface the way it is > implemented today. That it seems to work for you, is pure luck, I > guess. :)
Is there a safe/easy way to tell udev that we will handle a particular request? I cant say that I've ever seen any problems due to udev cancelling a firmware request. In fact, if I manually trigger a request using "echo" from the cmdline, I dont see udev take any action with the dell_rbu device. eg (Fedora 10, udev-127-5.fc10):
# find /sys -name dell_rbu /sys/devices/platform/dell_rbu /sys/bus/platform/devices/dell_rbu /sys/module/dell_rbu [root@duo dell_rbu]# echo "init" > /sys/devices/platform/dell_rbu/image_type [root@duo dell_rbu]# find /sys -name dell_rbu /sys/devices/platform/dell_rbu /sys/devices/platform/dell_rbu/firmware/dell_rbu /sys/bus/platform/devices/dell_rbu /sys/class/firmware/dell_rbu /sys/module/dell_rbu [root@duo dell_rbu]# ll /sys/class/firmware/dell_rbu/ total 0 -rw-r--r-- 1 root root 0 2009-04-29 16:25 data lrwxrwxrwx 1 root root 0 2009-04-29 16:25 device -> ../../../dell_rbu -rw-r--r-- 1 root root 4096 2009-04-29 16:25 loading drwxr-xr-x 2 root root 0 2009-04-29 16:25 power lrwxrwxrwx 1 root root 0 2009-04-29 16:25 subsystem -> ../../../../../class/firmware -rw-r--r-- 1 root root 4096 2009-04-29 16:25 uevent [root@duo dell_rbu]# [root@duo dell_rbu]# echo 0 > /sys/class/firmware/dell_rbu/loading [root@duo dell_rbu]# [root@duo dell_rbu]# find /sys -name dell_rbu /sys/devices/platform/dell_rbu /sys/bus/platform/devices/dell_rbu /sys/module/dell_rbu
I dont see any of the behaviour that you have talked about. If I let it sit there for hours, it will stay at that state. It only closes up the request_firmware() request when I echo 0 > loading.
At this point, we have had this interface in the upstream kernel.org kernel since 2.6.14 and have a pretty huge legacy codebase that relies on this behaviour. We need to make sure that the current behaviour remains.
-- Michael
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