Re: upping a semaphore from a USB completion handler?
Oliver Neukum <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
Am Freitag, 22. Juni 2007 schrieb Florin Iucha: > Hello, > > I am writing a USB driver for some custom hardware, and I need to > synchronize between the user-space and the USB subsystem. Can I > create a semaphore and "down" it in the reader then "up" it in the > completion handler? Yes, you can. > I know the completion handler runs in interrupt context so you are not > allowed to acquire any semaphores: but can you release them? Will the You can. > waiting tasks wake up after the handler and its caller returned - IOW > will the waking up task run in interrupt context as well? No, it will run or rather may run, as you have no guarantee that it'll be scheduled to run immediately, in its own context. Regards Oliver ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel