Hello Greg Am Mittwoch, den 12.09.2007, 03:01 -0700 schrieb Greg KH: > 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.
No thats not true. I thought this too, but if I make a: seek (fd, 0L, SEEK_SET); in Userspace, there is no retrigger in the sysFS, my driver is *not* called again. So I made a own sysfs_seek function, which does retrigger the driver ... Is this really wanted in the sysFS, that there is no way to retrigger a read? thanks Heiko -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev