Re: SMBIOS / DMI Event Logs in Linux?

Mike Waychison
2011-02-11T02:19:55Z

On 02/10/11 17:25, Greg KH wrote:
> On Thu, Feb 10, 2011 at 03:18:14PM -0800, Mike Waychison wrote:
>> Hey guys,
>>
>> I need some guidance. Do either of you know of any attempts to have
>> the kernel decode and display/interact with DMI type 15: System
>> Event Log?
>
> I don't have any experience in this area, but I do have one comment on
> your proposal below:
>
>> The event log I'm dealing with while cleaning up the "gsmi" driver
>> interacts with a log that is modeled after the System Event Log.
>> I'm wondering if there is any precedent for a clean way to expose
>> the event log, I'd like to use it (replacing the ioctls from my
>> earlier patch series send-out).
>>
>> FYI, we use OEM specific headers and descriptors, which probably
>> doesn't help.
>>
>> Do most folks that need access to this data rely on /dev/mem and
>> dmidecode? I'd like to avoid going that route if possible.
>>
>> Lacking any better ideas though, I was thinking of something along
>> the lines of the following:
>>
>>
>> $ cat /sys/firmware/gsmi/eventlog
>> <offset> <boot number> <recorded time> <quoted reason> <optional data>
>> ...
>>
>> with a single event log entry per line.
>> <offset> would be the record number,
>> <boot number> is the recorded boot number
>> <recorded time> comes from each record,
>> <quoted reason> is the English translation of Event Log Types from
>> the DMTF standard + vendor extended types we use.
>> <optional data> is space separated values associated with<quoted reason>
>
> Ick, no, remember, sysfs is "one value per file". doing even a single
> line like you describe here isn't ok, not to mention a huge buffer of
> these lines.
>
> And no, a "binary" sysfs file is not ok either.

Works fine for the /sys/firmware/efi stuff. Works well enough for
/sys/firmware/acpi too.

>
> Now your idea for such a log file is fine, I'm not saying that's not ok,
> or acceptable, just don't put it in sysfs, sorry. Try using the ring
> buffer framework from the tracing code perhaps?
>
> Or use debugfs? Or make a 'firmwarefs'? I can easily knock that
> together if you need it.

Are you seriously asking for another filesystem?

I don't get why you're holding me to these standards that that are
totally missed by these same subsystems that you maintain.