MOtherboard of HP z800 not supported

[Waywardnl]

Is it possible to add support for the HP z800 motherboard? I am willing to participate in the investigation

[koitsu]

Please see some of the project's existing tickets for details that I require to implement such support:

• ASROCK EP2C602-4L/D16 motherboard uses Nuvoton chip #4
• Support for ASRock X399 Professional Gaming motherboard #5
• Support for Supermicro X7DBU (Winbond W83627HF/F/HG/G & Winbond W83793G) #6 (good example of a mainboard/server vendor providing the necessary support, though sadly EOL status blocked getting the info)
• Rock64-PRO arm64 not supported #7

You will most likely have to communicate with HP Support to try and get low-level technical information (specifically if any/all hardware monitoring ICs on the mainboard are tied to SMBus, and if so, what SMBus slave address and description of registers).

I could not find this information in the HP Z800 User Manual; the closest I could find was mention of DASH which appears to be proprietary and the document does not provide the low-level technical details.

[koitsu]

Looks like some of the H/W monitoring may be driven by an SMSC SCH5327 (RevB) Super I/O controller. This is probably a SCH5327B-NS.

A completely unrelated project on GitHub contained this issue: CozmoNate/HWSensors#336

Within that post contains the link to https://www.kernel.org/doc/Documentation/hwmon/smsc47b397 which is some reverse-engineering documentation done by a couple individuals, circa 2004. However, this document is for the SCH5317, not the SCH5327; the latter is newer and may support SMBus tie-in, but it's unknown to me because no manufacturer details can be found on these chips. Worse, the document there describes how to interface with the chip using LPC (i.e. classic ISA I/O ports; think /dev/io or io(4) on FreeBSD), and not via SMBus. I do not have plans to implement LPC support given that if you get the base address wrong and have to issue writes to it, you can greatly risk system instability.

On the flip side, the SCH5627 (note the number difference) does support some degree of H/W monitoring over SMBus, but no idea if the SCH5237 does. Tthe SCH5027 seems to support it as well, or is implied by this site but there are variances between sub-models and revisions of chips, which is why having documentation for the specific chip is important.

One possibility would be to review the Linux lm-sensors project to see if they have reliable support for the SCH5327 and whether or not it offers an SMBus interface or not (most of the time I see lm-sensors use LPC).