Greg KH wrote: > On Wed, Sep 12, 2007 at 07:32:07AM +0200, Robert Schwebel wrote: >> On Tue, Sep 11, 2007 at 11:43:17AM +0200, Heiko Schocher wrote: >>> I have developed a device driver and use the sysFS to export some >>> registers to userspace. >> Uuuh, uggly. Don't do that. Device drivers are there to abstract things, >> not to play around with registers from userspace. >> >>> I opened the sysFS File for one register and did some reads from this >>> File, but I alwas becoming the same value from the register, whats not >>> OK, because they are changing. So I found out that the sysFS caches >>> the reads ... :-( >> Yes, it does. What you can do is close()ing the file handle between >> accesses, which makes it work but is slow. > > Do an lseek back to 0 and then re-read, you will get called in your > driver again.
There should be an intervening sysfs_notify() call from kernel side to make sysfs re-populate its cache on read again. sysfs bin files buffer the result but don't cache the result but this again doesn't really fit the usage case. Thanks. -- tejun - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
