[PATCH 1/2] smbios: Simplify reporting of unknown values

[Ilias Apalodimas]

Hi Sean

On Sat, 17 Sept 2022 at 19:55, Sean Anderson <seanga2 at gmail.com> wrote:
>
> On 9/16/22 16:30, Ilias Apalodimas wrote:
> > Hi Simon,
> >
> > [...]
> >
> >>> Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> >>> ---
> >>>   lib/smbios.c | 17 +++--------------
> >>>   1 file changed, 3 insertions(+), 14 deletions(-)
> >>
> >> Perhaps a better fix is to drop the smbios info?
> >
> > Unfortunately there's a ton of userspace tools still using it.  So I think
> > we still need it
> >
> >>
> >> What upstream projects use this information to show things to the
> >> user? You showed a screenshot of some sort of system-info app. We
> >> could teach it about falling back to the device tree. That way we are
> >> not adding fake information to SMBIOS.
> >>
> >
> > What's fake here?  The model and compatible are taken directly from the DT
> > and that should be accurate.  I'd rather fix the DT if that's problematic.
> > What would make sense for me to change is take the first token of the
> > compatible node instead of the entire string as it's format is expected to
> > be <manufacturer, model> anyway.
>
> >         Manufacturer: socionext,developer-box
> >         Product Name: Socionext Developer Box
>
> Well, firstly, the manufacturer is "Socionext", not
> "socionext,developer-box". Compatibles are not suitable for
> user-visible identifiers. The product name should also be something like
> "Socionext Developerbox" or maybe "SynQuacer E-series", but this more of
> a "bug" in the devicetree model property.

Yea as I said we can get rid of the everything after the ',' on the
compatible node.  Ideally if vendors followed the DT spec, we could
also just use manufacturer node,  the reality is that we can't though.
The whole point of the patchset is provide something reasonable
without having to add a .dtsi smbios node for all our devices.  We can
then go back to fixing the DT with proper values if it's a DT "bug".

>
> Second, these identifiers are not suitable for all structures you want
> to use it for. For example, the chassis is really a "INWIN industrial PC
> case: MicroATX mini-tower case IW-BK623/300-H E USB 3.0 Black with 300W
> SFX power supply" [1]. I would describe this as something like

The chassis isn't even addressed in the series.  IIRC it's currently
hardcoded in smbios.c.

>
> Handle 0x0003, DMI type 3, 21 bytes
> Chassis Information
>          Manufacturer: INWIN
>          Type: Mini Tower
>          Lock: Not Present
>          Version: Unknown
>          Serial Number: Not Specified
>          Asset Tag: Not Specified
>          Boot-up State: Safe
>          Power Supply State: Safe
>          Thermal State: Safe
>          Security Status: None
>          OEM Information: 0x00000000
>          Height: Unspecified
>          Number Of Power Cords: 1
>          Contained Elements: 0
>
> The exact values are not particularly important, but I would certainly
> classify a manufacturer of "socionext,developer-box" as fake. We might
> not even know what the chassis is; what's to stop a user from using a
> different case?

But the chassis isn't even addressed in the series?  Again I am mostly
interested in a sane fallback for device and manufacturer.

>
> [1] https://www.96boards.org/documentation/enterprise/developerbox/hardware-docs/MN04-00002-3E.pdf
>
> >> Also, SMBIOS is a legacy thing and a PITA to work with. How about we
> >> use the device tree binding for the same info:
> >>
> >>      smbios {
> >>          compatible = "u-boot,sysinfo-smbios";
> >>
> >>          smbios {
> >>              system {
> >>                  manufacturer = "pine64";
> >>                  product = "rock64_rk3328";
> >>              };
> >>
> >>              baseboard {
> >>                  manufacturer = "pine64";
> >>                  product = "rock64_rk3328";
> >>              };
> >>
> >>              chassis {
> >>                  manufacturer = "pine64";
> >>                  product = "rock64_rk3328";
> >>              };
> >>          };
> >>      };
> >>
> >> This is easy to parse and gets us away from all this legacy junk that
> >> we don't need.
> >
> > That's the exact opposite of the patch description.  Most of these info are
> > already included in the DT in it's standard properties.  So if U-Boot ends
> > up with a DT without these we get a usable smbios table.  For example a DT
> > handed over by the previous stage bootloader would not include these nodes.
>
> I agree. I think a better example would fill in these fields with
> descriptive values.

We are off to a chicken and egg problem now.  Can you provide U-Boot
with a  'configuration' DT, which would be disjoint from the DT that
describes hardware?

>
> > As far as sysinfo-smbios node is concerned,  it's only present in 13
> > boards, so it's not like  it's used by the majority of boards.  Yes we
> > could fix them, but imho we are better off re-using what's already there
> > and defined on the DT spec at least for the simplistic values.
>
> IMO SYS_VENDOR and SYS_BOARD are more descriptive than the devicetree
> values, but neither is good...

Didn't we use to do that? IOW fill in smbios nodes based on Kconfig
values.  But then we moved away from that in favor of the
sysinfo-smbios node, but a very small amount of boards got converted.

>
> How many boards do we have which actually use the SMBIOS tables? There
> are a lot of boards with EFI_LOADER enabled by default, but I suspect
> most never boot anything EFI.

I don't see how that's relevant?  If someone for any reason enables
smbios it shouldn't report always "Unknown".

Thanks
/Ilias
>
> --Sean