On Fri, Jun 29, 2018 at 9:56 PM, Stuart Hayes <stuart.w.hayes@xxxxxxxxx> wrote: > On 06/27/2018 06:52 PM, Andy Shevchenko wrote: >> On Fri, Jun 15, 2018 at 1:31 AM, Stuart Hayes <stuart.w.hayes@xxxxxxxxx> wrote: >>> On 6/14/2018 12:25 PM, Andy Shevchenko wrote: >>>> On Thu, Jun 14, 2018 at 5:22 PM, Stuart Hayes <stuart.w.hayes@xxxxxxxxx> wrote: >>>>> On 6/13/2018 3:54 AM, Andy Shevchenko wrote: >>>> Thanks, but here I meant += 1 vs += 16 step. > I did realize that the debug code that printed the address of the EPS table was not > working right, and the table on my system is actually 16-byte aligned. However, > the documentation on the EPS does not specify that it will be 16-byte aligned, so I > don't think the driver should make that assumption, especially since scanning a 64K > region byte by byte should take very little extra time over scanning every 16th byte. > I guess this isn't needed since the table on my system actually is 16-byte aligned. I think the 16 byte is a natural alignment applicable to all tables like a such. I would rather go with it until we will get a (weird) BIOS which does not support that. (I believe this alignment just comes by definition of C ABIs for the structures / types. So, each defined type is located on an aligned boundaries) >>> [ 4680.194012] dcdbas dcdbas: WSMT found, using firmware-provided SMI buffer. >>> [ 4680.195327] dcdbas dcdbas: Dell Systems Management Base Driver (version 5.6.0-3.3) >> >> OK, now the most important question, did you investigate "SMM >> Communication ACPI Table"? >> Can you utilize information in it? > Dell BIOS does not provide a "SMM Communication ACPI Table", just the EPS. It appears > that the "SMM Communication ACPI Table" is deprecated in the UEFI 2.7 spec. Also, the > dcdbas driver is for Dell systems only. > The EPS table isn't an ACPI table, > it's just a Dell-defined table. Hmm... It's either strange or has some background why is so. OK it has a note that there is no use case, but here it is! Mario, can we consider this as a BIOS bug which doesn't provide SMM Communication ACPI table? Can it be escalated on UEFI committee? -- With Best Regards, Andy Shevchenko
