Hi Jean, On 08.03.2016 15:13, Jean Delvare wrote: > Hi all, > > I am still working on the i2c-piix4 driver. The current state doesn't > look good, I see many problems. > > 1* We do not check which SMBus ports are enabled before accessing them. > So we create I2C buses which do not exist. I have a patch adding > support for this for the SB800. > > 2* Even if we only instantiate I2C buses for ports which do exist, that > doesn't mean they are used. Unused ports may have their pins left > floating by the hardware manufacturer, resulting in random behavior and > boot delays. I suspect this is what was reported at: > https://bugzilla.kernel.org/show_bug.cgi?id=112811 > I don't really have a solution for this. One possibility would be to > add a module parameter to specify which ports are present in case the > default leads to problems. Another possibility is to enable all ports > but disable device auto-detection on the extra ports, at least by > default. Yet another possibility is a DMI-based list of boards with > known mappings. Not sure what is best, maybe we need a mix of all that, > opinions welcome. > > Christian, please provide the DMI data for your board, in case we need > it later. Sure, see below. Thanks, Christian # dmidecode 2.12 SMBIOS 2.6 present. 35 structures occupying 1145 bytes. Table at 0x000FB330. Handle 0x0000, DMI type 0, 24 bytes BIOS Information Vendor: HP Version: O41 Release Date: 10/01/2013 Address: 0xF0000 Runtime Size: 64 kB ROM Size: 2048 kB Characteristics: ISA is supported PCI is supported PNP is supported BIOS is upgradeable BIOS shadowing is allowed ESCD support is available Boot from CD is supported Selectable boot is supported BIOS ROM is socketed EDD is supported 5.25"/1.2 MB floppy services are supported (int 13h) 3.5"/720 kB floppy services are supported (int 13h) 3.5"/2.88 MB floppy services are supported (int 13h) Print screen service is supported (int 5h) Serial services are supported (int 14h) Printer services are supported (int 17h) CGA/mono video services are supported (int 10h) ACPI is supported USB legacy is supported LS-120 boot is supported ATAPI Zip drive boot is supported BIOS boot specification is supported Targeted content distribution is supported BIOS Revision: 8.15 Handle 0x0001, DMI type 1, 27 bytes System Information Manufacturer: HP Product Name: ProLiant MicroServer Version: Serial Number: 5C7351P517 UUID: 1419D680-1DD2-11B2-8000-9CB6540B0F31 Wake-up Type: Power Switch SKU Number: 744900-421 Family: Handle 0x0002, DMI type 3, 21 bytes Chassis Information Manufacturer: HP Type: Tower Lock: Not Present Version: Serial Number: Asset Tag: 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 Handle 0x0003, DMI type 4, 42 bytes Processor Information Socket Designation: CPU 1 Type: Central Processor Family: Other Manufacturer: AMD ID: 63 0F 10 00 FF FB 8B 17 Version: AMD Turion(tm) II Neo N54L Dual-Core Processor Voltage: 1.1 V External Clock: 200 MHz Max Speed: 2200 MHz Current Speed: 2200 MHz Status: Populated, Enabled Upgrade: Other L1 Cache Handle: 0x0004 L2 Cache Handle: 0x0005 L3 Cache Handle: 0x0006 Serial Number: To Be Filled By O.E.M. Asset Tag: To Be Filled By O.E.M. Part Number: To Be Filled By O.E.M. Core Count: 2 Core Enabled: 2 Thread Count: 2 Characteristics: 64-bit capable Handle 0x0004, DMI type 7, 19 bytes Cache Information Socket Designation: L1-Cache Configuration: Enabled, Not Socketed, Level 1 Operational Mode: Varies With Memory Address Location: Internal Installed Size: 256 kB Maximum Size: 256 kB Supported SRAM Types: Pipeline Burst Installed SRAM Type: Pipeline Burst Speed: Unknown Error Correction Type: Single-bit ECC System Type: Data Associativity: 4-way Set-associative Handle 0x0005, DMI type 7, 19 bytes Cache Information Socket Designation: L2-Cache Configuration: Enabled, Not Socketed, Level 2 Operational Mode: Varies With Memory Address Location: Internal Installed Size: 2048 kB Maximum Size: 2048 kB Supported SRAM Types: Pipeline Burst Installed SRAM Type: Pipeline Burst Speed: Unknown Error Correction Type: Single-bit ECC System Type: Unified Associativity: 4-way Set-associative Handle 0x0006, DMI type 7, 19 bytes Cache Information Socket Designation: L3-Cache Configuration: Disabled, Not Socketed, Level 3 Operational Mode: Unknown Location: Internal Installed Size: 0 kB Maximum Size: 0 kB Supported SRAM Types: Unknown Installed SRAM Type: Unknown Speed: Unknown Error Correction Type: Unknown System Type: Unknown Associativity: Unknown Handle 0x0007, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: J13 Internal Connector Type: None External Reference Designator: Front USB External Connector Type: Access Bus (USB) Port Type: USB Handle 0x0008, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: J14 Internal Connector Type: None External Reference Designator: Front USB External Connector Type: Access Bus (USB) Port Type: USB Handle 0x0009, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: J15 Internal Connector Type: None External Reference Designator: Rear USB External Connector Type: Access Bus (USB) Port Type: USB Handle 0x000A, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: J15 Internal Connector Type: None External Reference Designator: LAN 1 External Connector Type: RJ-45 Port Type: Network Port Handle 0x000B, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: J16 Internal Connector Type: None External Reference Designator: VGA External Connector Type: DB-15 female Port Type: Video Port Handle 0x000C, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: J23 Internal Connector Type: None External Reference Designator: eSATA External Connector Type: SAS/SATA Plug Receptacle Port Type: SATA Handle 0x000D, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: J8 - MINISAS Internal Connector Type: SAS/SATA Plug Receptacle External Reference Designator: Not Specified External Connector Type: None Port Type: SATA Handle 0x000E, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: J20 -TPM Internal Connector Type: Other External Reference Designator: Not Specified External Connector Type: None Port Type: Other Handle 0x000F, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: J22 -FAN Internal Connector Type: Other External Reference Designator: Not Specified External Connector Type: None Port Type: Other Handle 0x0010, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: J24 - SATA ODD Internal Connector Type: SAS/SATA Plug Receptacle External Reference Designator: Not Specified External Connector Type: None Port Type: SATA Handle 0x0011, DMI type 8, 9 bytes Port Connector Information Internal Reference Designator: J33 - Internal USB Internal Connector Type: Access Bus (USB) External Reference Designator: Not Specified External Connector Type: None Port Type: USB Handle 0x0012, DMI type 9, 17 bytes System Slot Information Designation: PCIE1-J5 Type: x16 PCI Express Current Usage: Available Length: Short ID: 1 Characteristics: 3.3 V is provided Opening is shared PME signal is supported Handle 0x0013, DMI type 9, 17 bytes System Slot Information Designation: PCIE2-J6 Type: x1 PCI Express Current Usage: Available Length: Short ID: 2 Characteristics: 3.3 V is provided Opening is shared PME signal is supported Handle 0x0014, DMI type 16, 15 bytes Physical Memory Array Location: System Board Or Motherboard Use: System Memory Error Correction Type: Single-bit ECC Maximum Capacity: 8 GB Error Information Handle: Not Provided Number Of Devices: 2 Handle 0x0015, DMI type 19, 15 bytes Memory Array Mapped Address Starting Address: 0x00000000000 Ending Address: 0x002FFFFFFFF Range Size: 12 GB Physical Array Handle: 0x0014 Partition Width: 1 Handle 0x0016, DMI type 17, 28 bytes Memory Device Array Handle: 0x0014 Error Information Handle: Not Provided Total Width: 72 bits Data Width: 64 bits Size: 8192 MB Form Factor: DIMM Set: None Locator: DIMM0 Bank Locator: BANK0 Type: Other Type Detail: Synchronous Speed: 1333 MHz Manufacturer: Manufacturer00 Serial Number: SerNum00 Asset Tag: Not Specified Part Number: ModulePartNumber00 Rank: Unknown Handle 0x0017, DMI type 126, 19 bytes Inactive Handle 0x0018, DMI type 17, 28 bytes Memory Device Array Handle: 0x0014 Error Information Handle: Not Provided Total Width: 72 bits Data Width: 64 bits Size: 4096 MB Form Factor: DIMM Set: None Locator: DIMM1 Bank Locator: BANK1 Type: Other Type Detail: Synchronous Speed: 1333 MHz Manufacturer: Manufacturer01 Serial Number: SerNum01 Asset Tag: Not Specified Part Number: ModulePartNumber01 Rank: Unknown Handle 0x0019, DMI type 126, 19 bytes Inactive Handle 0x001A, DMI type 32, 20 bytes System Boot Information Status: No errors detected Handle 0x001B, DMI type 38, 18 bytes IPMI Device Information Interface Type: KCS (Keyboard Control Style) Specification Version: 2.0 I2C Slave Address: 0x10 NV Storage Device: Not Present Base Address: 0x0000000000000000 (Memory-mapped) Register Spacing: Successive Byte Boundaries Handle 0x001C, DMI type 193, 7 bytes OEM-specific Type Header and Data: C1 07 1C 00 00 01 02 Strings: 00/00/0000 01/12/2013 Handle 0x001D, DMI type 208, 5 bytes OEM-specific Type Header and Data: D0 05 1D 00 FF Handle 0x001E, DMI type 208, 5 bytes OEM-specific Type Header and Data: D0 05 1E 00 FF Handle 0x001F, DMI type 209, 12 bytes HP BIOS PXE NIC PCI and MAC Information NIC 1: PCI device 02:00.0, MAC address 9C:B6:54:0B:0F:31 Handle 0x0020, DMI type 224, 5 bytes OEM-specific Type Header and Data: E0 05 20 00 00 Handle 0x0021, DMI type 225, 12 bytes OEM-specific Type Header and Data: E1 0C 21 00 48 08 F1 FF 50 00 F0 FF Handle 0x0022, DMI type 127, 4 bytes End Of Table > > 3* For the Hudson-2/Bolton, according to the datasheet there is no > separate GPIO pin configuration registers for the SMBus ports. Pins are > GPIO when the corresponding SMBus port is not enabled, and SMBus when > the SMBus port is enabled. This means that it is impossible to detect > which SMBus ports exist, except for the one being currently selected. > Even worse, it means that activating any other SMBus port could send I/O > signals over GPIO pins which were meant for something completely > different. This has a potential for BREAKING THINGS BADLY, including > HARDWARE DAMAGE. Therefore I believe that multiplexing support should > be DISABLED by default on this hardware, as soon as possible. > > 4* Didn't check Mullins and Carrizo yet, but odds are they behave the > same as Hudson-2/Bolton, so I think we should disable them for the time > being too. > > 5* The I/O ports used for SMBus configuration and port switching are > also needed by a watchdog driver, sp5100_tco. Both drivers request the > region, so the first one wins, and the other driver can't be loaded. > sp5100_tco was there first, so the changes done to the i2c-piix4 driver > recently will cause a regression for some users by preventing them > from using the sp5100_tco and i2c-piix4 drivers at the same time. In > the long run I guess we will need a helper module to handle this shared > resource. Unless IORESOURCE_MUXED can be used for that. Either way, > that's more work than I can put into this before kernel v4.5 is > released. For the time being, I think we should simply make it > non-fatal if the I/O ports can't be requested, and continue without > multiplexing (as before.) > -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
