On Sun, 3 Jun 2018, Paul Goyette wrote:
On Sat, 2 Jun 2018, Jason Thorpe wrote:
On Jun 1, 2018, at 3:45 PM, Paul Goyette <[email protected]> wrote:
There is at least one i2c bus controller that explicitly doesn't
handle "quick" transactions - the imc controller built into the Intel
X99 chip-set. The docs are pretty clear that it implements an
absolute minimum subset of i2c, just barely enough to talk to the SPD
ROMs on memory DIMMs.
Wait, are you sure about that? The X99 data sheet explicitly says is
supports the SMBus ???quick??? command.
Hmmm, I must have mis-read or mis-understood something.
In any case, the current driver code doesn't seem to support "quick".
From src/sys/arch/x86/pci/imcsmb/imcsmb.c in routine imcsmb_exec() we
have:
if ((cmdlen != 1) || (len > 2) || (len < 1))
return EINVAL;
(If I remember correctly, the quick command has cmdlen == 0 which would fail
the first part of this test.)
For changing this, I'd have to defer to msaitoh@ (the author of the driver).
Please note that the X99 chip-set actually has two different SMBus
controllers!
There's the "minimal-functionality" controller that sits on the "system
management PCI bus" and driven by the imc/imcsmb driver. But there is
also a "full-function" SMbus at "pci0 dev 31 function 3" which uses the
ichsmb driver. It is the former device via which my spdmem and sdtemp
devices are accessed.
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