From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 9 Oct 2015 10:58:54 +0200 From: Gilles Chanteperdrix Message-ID: <20151009085854.GC5923@hermes.click-hack.org> References: <56139C8B.3060509@control.lth.se> <20151006192323.GB30765@hermes.click-hack.org> <5614C8E3.5090809@sigmatek.at> <5614D22A.8030203@sigmatek.at> <5615108A.6070001@control.lth.se> <20151007124107.GB30140@hermes.click-hack.org> <20151007144156.GC30140@hermes.click-hack.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Xenomai] Problems disabling SMI interrupts on MSI H87-G43 motherboard List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jeroen Van den Keybus Cc: "xenomai@xenomai.org" On Thu, Oct 08, 2015 at 11:08:46AM +0200, Jeroen Van den Keybus wrote: > >> >> Thanks everybody, seems like I have to give up on that motherboard: > >> >> > >> >> 1. Nothing found to disable in the BIOS > >> >> 2. Disabling all sourcecs with smictrl > >> >(git://git.kiszka.org/smictrl.git) > >> >> still gives high latencies with RTNet (+1.5 milliseconds). > >> >> 3. latency test does not show anything suspicious, so it might > >> >> be some other issue. > >> >> > >> >> Anybody that has a suggestion on a recent motherboard that has been > >> >used with > >> >> RTNet and showing good results? > > As you found out, most MB BIOSes set the SMI lock bit. No way around it. According to the documentation the SMI lock bit should only lock the SMI_EN register bit 0, that is the "global disable" bit. However, on the last machines where I had SMI issues, the SMI_EN register was entirely read-only, so there must be other ways than the SMI lock bit to lock the SMI_EN register, which is why smi.c write then reads the register, instead of checking the SMI lock bit. -- Gilles. https://click-hack.org