At Thu, 28 Sep 2006 18:02:34 +0100, James Courtier-Dutton wrote: > > Takashi Iwai wrote: > > At Wed, 27 Sep 2006 20:58:57 +0200 (CEST), > > Jaroslav Kysela wrote: > > > >> On Wed, 27 Sep 2006, James Courtier-Dutton wrote: > >> > >> > >>> Hi, > >>> > >>> The E-MU 1820m consists of a PCI card with a connector on it. > >>> A cable then runs to an external box called the AudioDock with all the > >>> audio IO on it. > >>> The AudioDock is hot pluggable. > >>> The problem is that no interrupts occur if one connects the AudioDock. > >>> One would have to poll the device until one saw a certain bit being set. > >>> One would then know the AudioDock was there. The driver then needs to > >>> load some firmware into the AudioDock. > >>> > >>> My question is, what should I use to monitor for the plug/unplug of the > >>> AudioDock? I would expect some user land app could do the polling, but > >>> that might require some new ALSA api to support it. > >>> > >> I would use a low resolution (probably ~1 sec) system timer to check this > >> bit and request the additional firmware in tasklet or workqueue. In this > >> case, the userland is not required to participate. > >> > > > > Agreed (tasklet cannot used for firmware loading, though). > > > > The unplug would be more tough, I guess. The driver has to accept > > that the box can be unplugged at any time. > > > > > > Takashi > > > > Ok, that's and interesting problem them, because about the only thing it > has to do when plugged in is load the firmware. > > So, if a tasklet it not useable for firmware loading, what should I use? A workqueue. > It is a shame that the kernel does not have a global poll function, > where one justs adds their function to a queue with minimum and maximum > poll intervals, and a single kernel task then steps through each one > doing the poll. What is the difference with a system timer? > If the poll returns true, the kernel should then > schedule a function to be run. This would use less task switching. A timer handler can schedule a workq. That's exactly what we suggested... Alternatively, you can make your workq task polling by itself. A work can reschedule itself with a certain delay. Takashi ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
