Hi Tomasz, On 06/29/2016 06:48 AM, Tomasz Nowicki wrote: > On 28.06.2016 18:12, Duc Dang wrote: >> On Tue, Jun 28, 2016 at 6:04 AM, Christopher Covington >> <cov@xxxxxxxxxxxxxx> wrote: >>> Hi Tomasz, >>> Ard's comments on v3 included: >>> >>> "... exact OEM table/rev id matches ..." >>> "... substring match ... out of the question ..." Digging through the archives I see Jon Master commented earlier to "be careful with substring match". >> I think having OEM Table ID as "PLAT " and then "PLAT2 " (the the >> next version of the SoC) is common. So yes, matching full string is >> better as we can use "PLAT2 " in MCFG table and not worry about the >> "PLAT" sub-string match causes the quirk to be applied >> unintentionally. > Note that platforms already shipped where OEM string has no padding will I'm confused by this statement. OEMID is defined as 6 bytes long and OEM Table ID as 8 bytes long in the ACPI specification. As far as I can tell, if your string isn't exactly that long, padding up to that length is required. > have change the firmware or add 0 padding to our quirk array IDs. The fixed 6 or 8 character string compare, as used v2 of this patchset, will be compatible with existing firmware as best I can tell. Adding padding to the quirk array IDs is exactly what I'm suggesting, although all the strings I've seen are space padded rather than null padded. Matches: {"APM ", "XGENE ", 1} {"CAVIUM", "THUNDERX", 1} {"HISI ", "HISI-D02", 1} {"HISI ", "HISI-D03", 1} {"QCOM ", "QDF2432 ", 1} Given the above tuples, won't accidentally match: (guessing at possible future ids) {"APM ", "XGENEi ", 1} {"CAVIUM", "THUNDERX", i} i != 1 {"CAVIUM", "THUNDERi", 1} {"CAVIUM", "THUNDRXi", 1} {"HISI ", "HISI-D0i", 1} i != 2 && i != 3 {"QCOM ", "QDF24ij ", 1} i != 3 && j != 2 References for APM, HiSilicon IDs: https://lists.linaro.org/pipermail/linaro-acpi/2016-June/007108.html https://lists.linaro.org/pipermail/linaro-acpi/2016-June/007043.html Thanks, Cov -- Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html