Re: [PATCH 1/3] i2c-piix4: Support alternative port selection register

[Jean Delvare <jdelvare@suse.de>]

On Sun, 14 Feb 2016 09:39:39 +0100, fetzerch wrote:
> Hi Jean,
> 
> On 13.02.2016 22:51, Jean Delvare wrote:
> > Hi Wolfram,
> > 
> > On Fri, 12 Feb 2016 20:27:20 +0100, Wolfram Sang wrote:
> >> On Fri, Jan 29, 2016 at 10:44:52AM +0100, Jean Delvare wrote:
> >>> The SB800 register reference guide says that the SMBus port selection
> >>> bits may not always be in register Smbus0En (0x2c) but could
> >>> alternatively be found in register Smbus0Sel (0x2e) depending on the
> >>> settings in register Smbus0SelEn (0x2f.) Add support for this
> >>> configuration.
> >>
> >> Were you able to test both cases?
> > 
> > I don't have the hardware myself so I was not able to test any case.
> > I was hoping Christian would test. This is the reason why I am logging
> > which register is used, so that we know if the alternative setting is
> > ever used. I found the potential problem by looking at the datasheet,
> > it's not something that has been reported (yet.)
> > 
> > Meanwhile I have found a datasheet for device 780Bh (named Bolton FCH
> > on AMD's web site, but Hudson2 in our driver) which suggest that the
> > "alternative" setting is the only possible one on this chipset. The
> > register used to figure out the setting is marked as reserved. If the
> > register exists still and the relevant bit is set, then my patch should
> > work. If not then a better patch will be needed.
> > 
> > I'll try to gain access to a system with a Bolton FCH and experiment
> > with it.
> > 
> > Then there's the most recent device, codenamed "CZ", for which I have
> > no information at all.
> > 
> 
> sorry for the late response. This time it slipped through on my side.
> 
> The sensors command still works fine without any noticable change.
> Here is the output:
> 
> [1894808.057493] piix4_smbus 0000:00:14.0: SMBus Host Controller at
> 0xb00, revision 0
> [1894808.057504] piix4_smbus 0000:00:14.0: Using register 0x2c for SMBus
> port selection
> [1894808.394960] i2c i2c-1: Found w83795adg rev. B at 0x2f
> [1894808.666968] piix4_smbus 0000:00:14.0: Auxiliary SMBus Host
> Controller at 0xb20

Thanks for testing, Christian, this is very helpful.

-- 
Jean Delvare
SUSE L3 Support