On Tue, 2006-09-26 at 16:56 +0200, gilles.chanteperdrix wrote: > ---------- Debut du message initial ----------- > > De : [EMAIL PROTECTED] > A : [EMAIL PROTECTED] > Copies : xenomai-core@gna.org > Date : Tue, 26 Sep 2006 16:21:18 +0200 > Objet : Re: [Xenomai-core] Problem with periodic timer on > PPC40x solved > > > > On Mon, 2006-09-25 at 22:29 +0200, Niklaus Giger wrote: > > > > > Am Montag, 25. September 2006 17:57 schrieb Philippe > Gerum: > > > > > > On Sun, 2006-09-24 at 23:07 +0200, Wolfgang > Grandegger wrote: > > > > > > > Niklaus Giger wrote: > > > <..> > > > > > Is the output of lines like "Xenomai: Switching > display-3238 to secondary > > > > > mode after exception #1025 from user-space at > 0x100033c4 (pid 3240)" > > > > > harmless or the result of a activated > CONFIG_XENO_OPT_DEBUG<..> option? > > > > A known hw issue seems to exist with the 405GP (revD), which > causes the > > ESR to be incorrectly set upon FPU emulation trap, which > would in turn > > cause the spurious exception to be relayed to the nucleus by > Adeos. The > > patch below is _not_ the final fix, but rather a way to > check if this > > message is indeed related to the FPU emulation on your > board. Does it > > silence the exception without breaking the box? > > The FPU fault may be the result of the latency display thread > using the > FPU: on systems with emulated FPU, this looks normal. >
This said, we should not switch the task to secondary mode, but rather emulate the FPU ops in primary mode. To this end, we need to make sure that do_mathemu() is not going to choke over this context (e.g. preemption count check issues over CONFIG_PREEMPT when running unmodified uaccess routines). We additionally need to fix the program check exception handler to give the math emulation code a chance to handle the fault before we complain loudly at the nucleus. -- Philippe. _______________________________________________ Xenomai-core mailing list Xenomai-core@gna.org https://mail.gna.org/listinfo/xenomai-core
