Date:	Wed, 29 Jun 2016 09:38:50 -0600
From:	Jeffrey Hugo <jhugo@...eaurora.org>
To:	Tomasz Nowicki <tn@...ihalf.com>,
	Christopher Covington <cov@...eaurora.org>,
	Duc Dang <dhdang@....com>
Cc:	Gabriele Paoloni <gabriele.paoloni@...wei.com>,
	Rafael Wysocki <rafael@...nel.org>, linux-pci@...r.kernel.org,
	Will Deacon <will.deacon@....com>,
	Sinan Kaya <okaya@...eaurora.org>,
	Yijing Wang <wangyijing@...wei.com>,
	Andrea Gallo <andrea.gallo@...aro.org>,
	Lorenzo Pieralisi <Lorenzo.Pieralisi@....com>,
	linaro-acpi@...ts.linaro.org,
	David Daney <ddaney@...iumnetworks.com>,
	linux-acpi@...r.kernel.org,
	Robert Richter <robert.richter@...iumnetworks.com>,
	Bjorn Helgaas <helgaas@...nel.org>,
	Dongdong Liu <liudongdong3@...wei.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Liviu Dudau <Liviu.Dudau@....com>,
	Arnd Bergmann <arnd@...db.de>, Jon Masters <jcm@...hat.com>,
	Mark Salter <msalter@...hat.com>,
	Marcin Wojtas <mw@...ihalf.com>,
	linux-arm <linux-arm-kernel@...ts.infradead.org>,
	Jayachandran C <jchandra@...adcom.com>,
	Ard Biesheuvel <ard.biesheuvel@...aro.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	jeremy.linton@....com, Hanjun Guo <hanjun.guo@...aro.org>
Subject: Re: [RFC PATCH v4 3/5] PCI: Check platform specific ECAM quirks

On 6/29/2016 7:52 AM, Tomasz Nowicki wrote:
> On 29.06.2016 15:34, Christopher Covington wrote:
>> 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.
>
> Well, I cannot find that requirement in ACPI spec. but I might missed
> something.

Have a look at table 5-29 in Section 5.2.6 which starts on page 114 of 
ACPI 6.1

>
> I dumped my x86 machine ACPI tables and here is an example of MCFG:
>
> $ cat mcfg.dsl
> /*
>  * Intel ACPI Component Architecture
>  * AML/ASL+ Disassembler version 20160108-64
>  * Copyright (c) 2000 - 2016 Intel Corporation
>  *
>  * Disassembly of mcfg.dat, Wed Jun 29 15:48:16 2016
>  *
>  * ACPI Data Table [MCFG]
>  *
>  * Format: [HexOffset DecimalOffset ByteLength]  FieldName : FieldValue
>  */
>
> [000h 0000   4]                    Signature : "MCFG"    [Memory Mapped
> Configuration table]
> [004h 0004   4]                 Table Length : 0000003C
> [008h 0008   1]                     Revision : 01
> [009h 0009   1]                     Checksum : A9
> [00Ah 0010   6]                       Oem ID : "ALASKA"
> [010h 0016   8]                 Oem Table ID : "A M I"
> [018h 0024   4]                 Oem Revision : 01072009
> [01Ch 0028   4]              Asl Compiler ID : "MSFT"
> [020h 0032   4]        Asl Compiler Revision : 00000097
>
> [024h 0036   8]                     Reserved : 0000000000000000
>
> [02Ch 0044   8]                 Base Address : 00000000F8000000
> [034h 0052   2]         Segment Group Number : 0000
> [036h 0054   1]             Start Bus Number : 00
> [037h 0055   1]               End Bus Number : 3F
> [038h 0056   4]                     Reserved : 00000000
>
> Raw Table Data: Length 60 (0x3C)
>
> 00000000  4d 43 46 47 3c 00 00 00  01 a9 41 4c 41 53 4b 41
> |MCFG<.....ALASKA|
> 00000010  41 20 4d 20 49 00 00 00  09 20 07 01 4d 53 46 54  |A M I....
> ..MSFT|
> 00000020  97 00 00 00 00 00 00 00  00 00 00 00 00 00 00 f8
> |................|
> 00000030  00 00 00 00 00 00 00 3f  00 00 00 00              |.......?....|
>
> So in this example I have OEM table ID "A M I" 6 character long and 0
> padding.
>
> Tomasz
>
>
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-- 
Jeffrey Hugo
Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a 
Linux Foundation Collaborative Project

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