Re: EDAC support for Arrow Lake-HX (8086:7d1c) - working out-of-tree driver, test hardware available

Hello Zura,

On 7/16/2026 1:55 PM, Emba Consulting wrote:
> On 7/16/2026 2:39 PM, Chaoyi Chen wrote:
>> I have an Intel Core Ultra 7 270K Plus (Arrow Lake-S Refresh), and it
>> appears to be 8086:7d1a. I'll test your driver, thanks!
> 
> Good to hear. Two heads-ups before you build:
> 
> - The module's ID table previously matched only 7d1c; I've pushed a
>   commit adding 7d1a (reusing the ARL-HX register map unchanged), so
>   pull https://github.com/zs311521/edac-arl-hx first or it won't bind.
> - mchbar-probe.py assumed my board's MCHBAR base; it now reads it
>   from PCI 00:00.0 config the way the driver does, so pull that too.
> 
> Suggested order on your machine:
> 
> 1. mchbar-probe.py (read-only, /dev/mem): it decodes MAD_DIMM and
>    ECCERRLOG from userspace. If the topology it prints doesn't match
>    your physical DIMM population, the ARL-S Refresh layout differs
>    from ARL-HX and the module's counts shouldn't be trusted - the
>    probe output is useful either way.
> 
> 2. modprobe/insmod. The defaults never write to hardware (polling
>    only, no MSR 0x791, no ERRSTS clear), so a load is safe even if
>    the die differs. It refuses with "No ECC support" if CAPID0 says
>    ECC is disabled.
> 
> Output worth sharing: lspci -nn -s 00:00.0,
> dmidecode -t 16 -t 17, the probe script output, and dmesg after load.
> And if your board exposes an ACPI EINJ table, injecting a corrected
> error would exercise the decode end to end - my BIOS has none, so
> that is the one path I have not been able to validate.
> 
> Thanks.
> 

I did a quick test, and it seems to be working properly :)

The output for your information:

$ lspci -nn -s 00:00.0
00:00.0 Host bridge [0600]: Intel Corporation Device [8086:7d1a] (rev 01)

$ sudo dmidecode -t 16 -t 17
# dmidecode 3.6
Getting SMBIOS data from sysfs.
SMBIOS 3.8.0 present.
# SMBIOS implementations newer than version 3.7.0 are not
# fully supported by this version of dmidecode.

Handle 0x000E, DMI type 16, 23 bytes
Physical Memory Array
	Location: System Board Or Motherboard
	Use: System Memory
	Error Correction Type: Single-bit ECC
	Maximum Capacity: 128 GB
	Error Information Handle: Not Provided
	Number Of Devices: 4

Handle 0x000F, DMI type 17, 92 bytes
Memory Device
	Array Handle: 0x000E
	Error Information Handle: Not Provided
	Total Width: Unknown
	Data Width: Unknown
	Size: No Module Installed
	Form Factor: Unknown
	Set: None
	Locator: Controller0-ChannelA-DIMM0
	Bank Locator: BANK 0
	Type: Unknown
	Type Detail: None

Handle 0x0010, DMI type 17, 92 bytes
Memory Device
	Array Handle: 0x000E
	Error Information Handle: Not Provided
	Total Width: Unknown
	Data Width: Unknown
	Size: No Module Installed
	Form Factor: Unknown
	Set: None
	Locator: Controller0-ChannelA-DIMM1
	Bank Locator: BANK 0
	Type: Unknown
	Type Detail: None

Handle 0x0011, DMI type 17, 92 bytes
Memory Device
	Array Handle: 0x000E
	Error Information Handle: Not Provided
	Total Width: Unknown
	Data Width: Unknown
	Size: No Module Installed
	Form Factor: Unknown
	Set: None
	Locator: Controller0-ChannelB-DIMM0
	Bank Locator: BANK 1
	Type: Unknown
	Type Detail: None

Handle 0x0012, DMI type 17, 92 bytes
Memory Device
	Array Handle: 0x000E
	Error Information Handle: Not Provided
	Total Width: 80 bits
	Data Width: 64 bits
	Size: 32 GB
	Form Factor: DIMM
	Set: None
	Locator: Controller0-ChannelB-DIMM1
	Bank Locator: BANK 1
	Type: DDR5
	Type Detail: Synchronous
	Speed: 5600 MT/s
	Manufacturer: Micron Technology
	Serial Number: 44343856
	Asset Tag: 9876543210
	Part Number: MTC20C2085S1EC56BD1 
	Rank: 2
	Configured Memory Speed: 5600 MT/s
	Minimum Voltage: 1.1 V
	Maximum Voltage: 1.1 V
	Configured Voltage: 1.1 V
	Memory Technology: DRAM
	Memory Operating Mode Capability: Volatile memory
	Firmware Version: Not Specified
	Module Manufacturer ID: Bank 1, Hex 0x2C
	Module Product ID: Unknown
	Memory Subsystem Controller Manufacturer ID: Unknown
	Memory Subsystem Controller Product ID: Unknown
	Non-Volatile Size: None
	Volatile Size: 32 GB
	Cache Size: None
	Logical Size: None

$ dmesg

[965428.124209] edac_arl_hx: loading out-of-tree module taints kernel.
[965428.124215] edac_arl_hx: module verification failed: signature and/or required key missing - tainting kernel
[965428.125593] resource: resource sanity check: requesting [mem 0x00000000fedc0000-0x00000000fedcffff], which spans more than PNP0C02:04 [mem 0xfedc0000-0xfedc7fff]
[965428.125597] caller arl_init_one+0xe2/0x640 [edac_arl_hx] mapping multiple BARs
[965428.125601] EDAC arl_hx: CAPID0[1]=0x21 (PDCD=0), MAD_DIMM_CH1=0x00000220
[965428.125619] EDAC arl_hx: mc 0 ch 0 dimm 0: 0 MiB, 1 rank(s), type 4
[965428.125620] EDAC arl_hx: mc 0 ch 0 dimm 1: 0 MiB, 1 rank(s), type 4
[965428.125621] EDAC arl_hx: mc 0 ch 1 dimm 0: 16384 MiB, 2 rank(s), type 4
[965428.125622] EDAC arl_hx: mc 0 ch 1 dimm 1: 0 MiB, 1 rank(s), type 4
[965428.125646] EDAC MC0: Giving out device to module arl_hx_edac controller ARL_HX: DEV 0000:00:00.0 (POLLED)
[965428.125660] EDAC arl_hx: CAPID0[1]=0x21 (PDCD=0), MAD_DIMM_CH1=0x00000220
[965428.125668] EDAC arl_hx: mc 1 ch 0 dimm 0: 0 MiB, 1 rank(s), type 4
[965428.125669] EDAC arl_hx: mc 1 ch 0 dimm 1: 0 MiB, 1 rank(s), type 4
[965428.125670] EDAC arl_hx: mc 1 ch 1 dimm 0: 16384 MiB, 2 rank(s), type 4
[965428.125671] EDAC arl_hx: mc 1 ch 1 dimm 1: 0 MiB, 1 rank(s), type 4
[965428.125685] EDAC MC1: Giving out device to module arl_hx_edac controller ARL_HX_1: DEV 0000:00:00.0 (POLLED)
[965428.125686] EDAC arl_hx: registered 2 IMC(s), mode=poll, clear=read-only

---

Unfortunately, my motherboard doesn't seem to have an option to allow EINJ.
After quickly reviewing Intel's manual, I have essentially the same
questions as you.

-- 
Best, 
Chaoyi