[linux-usb-devel] upping a semaphore from a USB completion handler?
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? 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 waiting tasks wake up after the handler and its caller returned - IOW will the waking up task run in interrupt context as well? This is with Linux 2.4 (if it makes a difference). Thanks, florin -- Bruce Schneier expects the Spanish Inquisition. http://geekz.co.uk/schneierfacts/fact/163 signature.asc Description: Digital signature - 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/___ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
Re: [linux-usb-devel] upping a semaphore from a USB completion handler?
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/ ___ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
