Re: SMBus not found

Re: SMBus not found

[Jean Delvare]

Hi Hrvoje,

Please use plain text (no HTML) when writing to development lists.

On jeu., 2017-02-02 at 14:50 +0100, Hrvoje T wrote:
> When I run sensors-detect I get an answer:
> Do you want to probe the I2C/SMBus adapters now? (YES/no): yes
> Sorry, no supported PCI bus adapters found.
> Is tehere anything else I can try?

You did not tell which version of sensors-detect you tried, nor what
kernel you are running, nor what your hardware is. What kind of help
are you expecting?

You should probably not be using sensors-detect in the first place
anyway. i2cdetect (from the i2c-tools package) is a much better tool
for what you are trying to do.

> Is it possible to dump addresses 0x50-0x57 on this bus with i2cdump
> and run decode-dimms -x on them? How could I do this when I don't
> know which bus is SMBus?

This question makes no sense as "this bus" is clearly undefined at this
point. First check what I2C/SMBus busses are available on your system:

# modprobe i2c-dev
# i2cdetect -l

Then either run i2cdetect / i2cdump on the relevant bus if it was
listed, or try to figure out why it is not listed (looking for it with
lspci maybe, if your SMBus controller is a PCI device.)

-- 
Jean Delvare
SUSE L3 Support

Re: SMBus not found

[Hrvoje T]

Hi Jean,

thank you for a quick reply.

My hardware is HP Probook 6470b laptop, kernel 4.8.0-37-generic,
lm-sensors version 1:3.4.0-3. I did

# modprobe i2c-dev
# i2cdetect -l

and got this:

i2c-3   i2c     i915 gmbus dpc       I2C adapter
i2c-1   i2c     i915 gmbus vga       I2C adapter
i2c-8   i2c     DPDDC-D              I2C adapter
i2c-6   i2c     DPDDC-B              I2C adapter
i2c-4   i2c     i915 gmbus dpb       I2C adapter
i2c-2   i2c     i915 gmbus panel     I2C adapter
i2c-0   i2c     i915 gmbus ssc       I2C adapter
i2c-7   i2c     DPDDC-C              I2C adapter
i2c-5   i2c     i915 gmbus dpd       I2C adapter


I would like to find out CAS latency times of my RAM memory modules
without opening the laptop. I guess those are on DIMM slots. dmidecode
-t memory gives:

Handle 0x0008, DMI type 17, 34 bytes
Memory Device
       Array Handle: 0x0005
       Error Information Handle: Not Provided
       Total Width: 64 bits
       Data Width: 64 bits
       Size: 4096 MB
       Form Factor: SODIMM
       Set: None
       Locator: Bottom-Slot 2(under)
       Bank Locator: BANK 2
       Type: DDR3
       Type Detail: Synchronous
       Speed: 1600 MHz
       Manufacturer: Ramaxel
       Serial Number: 44BBE80E
       Asset Tag: 9876543210
       Part Number: RMT3160ED58E9W1600
       Rank: Unknown
       Configured Clock Speed: Unknown


and lspci:

00:00.0 Host bridge: Intel Corporation 3rd Gen Core processor DRAM
Controller (rev 09)
00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core
processor Graphics Controller (rev 09)
00:14.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset
Family USB xHCI Host Controller (rev 04)
00:16.0 Communication controller: Intel Corporation 7 Series/C210
Series Chipset Family MEI Controller #1 (rev 04)
00:19.0 Ethernet controller: Intel Corporation 82579V Gigabit Network
Connection (rev 04)
00:1a.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset
Family USB Enhanced Host Controller #2 (rev 04)
00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset
Family High Definition Audio Controller (rev 04)
00:1c.0 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset
Family PCI Express Root Port 1 (rev c4)
00:1c.1 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset
Family PCI Express Root Port 2 (rev c4)
00:1c.2 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset
Family PCI Express Root Port 3 (rev c4)
00:1c.3 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset
Family PCI Express Root Port 4 (rev c4)
00:1d.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset
Family USB Enhanced Host Controller #1 (rev 04)
00:1f.0 ISA bridge: Intel Corporation HM76 Express Chipset LPC
Controller (rev 04)
00:1f.2 SATA controller: Intel Corporation 7 Series Chipset Family
6-port SATA Controller [AHCI mode] (rev 04)
23:00.0 FireWire (IEEE 1394): JMicron Technology Corp. IEEE 1394 Host
Controller (rev 30)
23:00.1 System peripheral: JMicron Technology Corp. SD/MMC Host
Controller (rev 30)
23:00.2 SD Host controller: JMicron Technology Corp. Standard SD Host
Controller (rev 30)
24:00.0 Network controller: Broadcom Limited BCM43228 802.11a/b/g/n


I know I could find out latency times on the manufacturer's web page,
but I would like to know is it possible via i2c? I'm noob in Linux and
bad at english, sorry for my mistakes and thanks for your help in
advance.

BR
Hrvoje

*trying without html from gmail one more time

Re: SMBus not found

[Jean Delvare]

Hi Hrvoje,

On Sat, 4 Feb 2017 02:55:02 +0100, Hrvoje T wrote:
> My hardware is HP Probook 6470b laptop, kernel 4.8.0-37-generic,
> lm-sensors version 1:3.4.0-3. I did
> 
> # modprobe i2c-dev
> # i2cdetect -l
> 
> and got this:
> 
> i2c-3   i2c     i915 gmbus dpc       I2C adapter
> i2c-1   i2c     i915 gmbus vga       I2C adapter
> i2c-8   i2c     DPDDC-D              I2C adapter
> i2c-6   i2c     DPDDC-B              I2C adapter
> i2c-4   i2c     i915 gmbus dpb       I2C adapter
> i2c-2   i2c     i915 gmbus panel     I2C adapter
> i2c-0   i2c     i915 gmbus ssc       I2C adapter
> i2c-7   i2c     DPDDC-C              I2C adapter
> i2c-5   i2c     i915 gmbus dpd       I2C adapter

No SMBus here, all the I2C buses listed are from your graphics chip.

> I would like to find out CAS latency times of my RAM memory modules
> without opening the laptop. I guess those are on DIMM slots. dmidecode
> -t memory gives:
> 
> Handle 0x0008, DMI type 17, 34 bytes
> Memory Device
>        Array Handle: 0x0005
>        Error Information Handle: Not Provided
>        Total Width: 64 bits
>        Data Width: 64 bits
>        Size: 4096 MB
>        Form Factor: SODIMM
>        Set: None
>        Locator: Bottom-Slot 2(under)
>        Bank Locator: BANK 2
>        Type: DDR3
>        Type Detail: Synchronous
>        Speed: 1600 MHz
>        Manufacturer: Ramaxel
>        Serial Number: 44BBE80E
>        Asset Tag: 9876543210
>        Part Number: RMT3160ED58E9W1600
>        Rank: Unknown
>        Configured Clock Speed: Unknown

Looks good, but DMI doesn't provide detailed timing information, only
speed.

> and lspci:
> (...)
> 00:1f.0 ISA bridge: Intel Corporation HM76 Express Chipset LPC
> Controller (rev 04)
> 00:1f.2 SATA controller: Intel Corporation 7 Series Chipset Family
> 6-port SATA Controller [AHCI mode] (rev 04)

The SMBus should show up as device 00:1f.3 here, but it is missing. It
means it has been hidden by the BIOS. We have some quirks in the kernel
to unhide the SMBus on older Intel chipsets, up to ICH6, but nothing for
recent chipsets.

> I know I could find out latency times on the manufacturer's web page,
> but I would like to know is it possible via i2c? I'm noob in Linux and
> bad at english, sorry for my mistakes and thanks for your help in
> advance.

It would be possible if the BIOS did not hide the SMBus device. But not
on your laptop, at least not until someone adds another PCI quirk to
unhide this specific device after reading its datasheet.

You may try booting memtest86 on your laptop (many Linux distributions
include it on their installation media), it may be able to display the
timing information you are looking for.

Alternatively, temporarily put the memory module in question in another
laptop where the SMBus is not hidden, and capture a dump of the SPD
data.

-- 
Jean Delvare
SUSE L3 Support