Date: Tue, 12 Aug 2003 16:54:09 +0200 From: Stijn Hoop <stijn@win.tue.nl> To: Igor Pokrovsky <igor.pokrovsky@cnrm.meteo.fr>, Don Bowman <don@sandvine.com>, freebsd-stable@freebsd.org Subject: Re: support of SMBus on ICH3 Message-ID: <20030812145409.GC59732@pcwin002.win.tue.nl> In-Reply-To: <20030812144000.GA4013@exmatis1.cnrm.meteo.fr> References: <FE045D4D9F7AED4CBFF1B3B813C853370274224D@mail.sandvine.com> <20030812134634.GA3783@exmatis1.cnrm.meteo.fr> <20030812140550.GZ59732@pcwin002.win.tue.nl> <20030812141318.GA59732@pcwin002.win.tue.nl> <20030812144000.GA4013@exmatis1.cnrm.meteo.fr>
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--keoAwTxaagou87Dg Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Aug 12, 2003 at 04:40:00PM +0200, Igor Pokrovsky wrote: > On Tue, Aug 12, 2003 at 04:13:18PM +0200, Stijn Hoop wrote: > > On Tue, Aug 12, 2003 at 04:05:50PM +0200, Stijn Hoop wrote: > > > 1000011000001001 > > >=20 > > > which shows that bit 3 is not set counting either way :( > >=20 > > Doh. I need more coffee. Obviously bit 3 _is_ set. > >=20 > > The question remains then: > >=20 > > > So how do I set this permanently? What determines the initial value > > > of this register? It doesn't survive a reboot :( Admittedly I'm in > > > above my head now. >=20 > So, 0 and 3 bits are set by default? Right? > What prevents us from detecting SMBus then? The fact that those bits are set by default on boot. From the manual: bit name =09 3 D31_F3_Disable R/W. Software sets this bit to disable the SMBus Host Controller function. BIOS must not enable I/O or memory address space decode, interrupt generation, or any other functionality of functions that are to be disabled. 0 =3D SMBus controller is enabled. 1 =3D SMBus controller is disabled. 0 SMB_FOR_BIOS R/W. This bit is used in conjunction with bit 3 in this register. 0 =3D No effect. 1 =3D Allows the SMBus I/O space to be accessible by software when bit 3 in this register is set. The PCI configuration space is hidden in this case. Note that if bit 3 is set alone, the decode of both SMBus PCI configuration and I/O space will be disabled. Both bits are set, so 'the SMBus I/O space' is accessible (whatever that means). I suspect Don is right, and the motherboard disables the SMBus controller becase there are no slave devices wired to it. Dell (the brand of my laptop) uses ACPI and a proprietary method to determine thermal values, so they must have disabled SMBus to avoid implementing yet another way to read those. If there was an ichsmb kernel module, you could theoretically clear the above bits, and _then_ load the module -- it should attach. I didn't see any method through adding quirks to always do this on boot though. --Stijn --=20 Nostalgia ain't what it used to be. --keoAwTxaagou87Dg Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (FreeBSD) iD8DBQE/OP+RY3r/tLQmfWcRAnXbAKCbCtg8Q+EsmdbtPo9PE2XZXisNbwCfbQ8W b9lTJd9t8939dqAmyS6JG2Q= =pJ95 -----END PGP SIGNATURE----- --keoAwTxaagou87Dg--
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