[lm-sensors] [PATCH 79/79] hwmon: (it87) Fix vrm value range
khali at linux-fr.org
Thu Jan 26 22:03:43 CET 2012
On Wed, 25 Jan 2012 02:31:39 -0800, Guenter Roeck wrote:
> On Wed, Jan 25, 2012 at 05:17:24AM -0500, Jean Delvare wrote:
> > There are 3 different problems here.
> > Problem #1 is the bug in hwmon-vid which causes all unknown Intel
> > family 6 processors to use VRM 8.2, even though this is wrong on any
> > post-2007 CPU.
> Working on fixing that. Looks like all the recent CPUs use VRD 11.0 or 11.1.
> There seem to be some supporting VRD 12.0, (the SandyBridge chips using the
> larger socket) but I did not find cpuid values for those.
There may be a problem with CPU models which can support an alternative
VID encoding for compatibility. I seem to recall that the early VRD
11.0 CPUs could also output VRD 10.x, but I could never find out how to
know when the actually did that.
> > Problem #2 is that unknown VRM for a recent CPU will only be notified
> > to the kernel log, which regular users don't read. Then you indeed get
> > a cpu0_vid value of 0. That's apparently what you were seeing on your
> > system. It would certainly be better to _not_ expose the VID value at
> > all if we don't know how to decode it.
> Actually, I have problem #1 on one board, and problem #3 on the other
> (the one with SandyBridge). vid reads 0xff on that board. On the other board,
> vid erroneously reports a voltage of 2.048V. I never thought about that
> until you brought it up.
2.050 V actually, this is 0x00 decoded as VRM 8.2.
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