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lscpu: use maximum CPU speed from DMI, avoid duplicate version string #3694

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lscpu: use maximum CPU speed from DMI, avoid duplicate version string #3694

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  • Read maximum CPU speed from DMI
  • Don't use max speed if nonsensical
  • Avoid appending "CPU @ speed" to the version string if it's already included. (This is a code robustness improvement as DMI is currently read for ARMs only, and the issue was detected on Intel.)

Fixes: a772d7c

@karelzak
lscpu: use maximum CPU speed from DMI, avoid duplicate version string
c332544 
* Read maximum CPU speed from DMI
* Don't use max speed if nonsensical
* Avoid appending "CPU @ speed" to the version string if it's already included.
  (This is a code robustness improvement as DMI is currently read for ARMs only,
   and the issue was detected on Intel.)

Fixes: util-linux@a772d7c
Signed-off-by: Karel Zak <kzak@redhat.com>
karelzak referenced this pull request Aug 21, 2025
@HuangShijie2024 @karelzak
lscpu: get the processor information by DMI
a772d7c 
The patch :367c85c47286 ("lscpu: use SMBIOS tables on ARM for lscpu")
relies on the existence of "/sys/firmware/dmi/entries/4-0/raw",
which may not exist in standard linux kernel.

But "/sys/firmware/dmi/tables/DMI" should exist and can provide the required
processor information.

This patch uses "/sys/firmware/dmi/tables/DMI"
to get the processor information:

Before this patch, in Ampere Altra platform, the lscpu output is:
   ---------------------------------------------
	Architecture:                    aarch64
	CPU op-mode(s):                  32-bit, 64-bit
	Byte Order:                      Little Endian
	CPU(s):                          160
	On-line CPU(s) list:             0-159
	Vendor ID:                       ARM
	Model name:                      Neoverse-N1
	Model:                           1
	Thread(s) per core:              1
	Core(s) per socket:              80
	Socket(s):                       2
    ........................................
   ---------------------------------------------

After this patch, we can use get the lscpu output
in Ampere Altra platform:
   ---------------------------------------------
	Architecture:                    aarch64
	CPU op-mode(s):                  32-bit, 64-bit
	Byte Order:                      Little Endian
	CPU(s):                          160
	On-line CPU(s) list:             0-159
	Vendor ID:                       ARM
	BIOS Vendor ID:                  Ampere(R)
	Model name:                      Neoverse-N1
	BIOS Model name:                 Ampere(R) Altra(R) Processor Q00-00 CPU @ 3.0GHz
	Model:                           1
	Thread(s) per core:              1
	Core(s) per socket:              80
	Socket(s):                       2
    ........................................
   ---------------------------------------------

[kzak@redhat.com: - s/sprintf/snprintf/]

Signed-off-by: Huang Shijie <shijie@os.amperecomputing.com>
Signed-off-by: Karel Zak <kzak@redhat.com>
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@karelzak