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Ampere(R) Altra(R) Processor - CPU Detection Error #236

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ozanMSFT opened this issue Apr 11, 2024 · 0 comments · Fixed by #237
Closed

Ampere(R) Altra(R) Processor - CPU Detection Error #236

ozanMSFT opened this issue Apr 11, 2024 · 0 comments · Fixed by #237

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@ozanMSFT
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ozanMSFT commented Apr 11, 2024 •
edited

Summary:

PR 220 has introduced an index problem that is preventing the retrieval of correct CPU information for Windows ARM64 systems using Ampere(R) Altra(R) Processor.

Found by: @iremyux

Details:

The main reason is the incompatibility between woa_chip_name (windows-arm-init.h) and woa_chips[] (init.c).

Since woa_chip_name_microsoft_sq_3 is duplicated, this for loop is not reaching the Ampere(R) Altra(R) Processor element in the array due to wrong size.

Error:

"Unknown chip model name 'Ampere(R) Altra(R) Processor'.
Please add new Windows on Arm SoC/chip support to arm/windows/init.c!"

cc: @iremyux, @malfet
@ozanMSFT ozanMSFT mentioned this issue Apr 11, 2024
Merged
malfet pushed a commit that referenced this issue Apr 17, 2024
@ozanMSFT
Fixing Ampere Altra Processor detection (#237)
5de5c70 
**Summary:**

Resolves #236

Also related to [PR 220](#220) change.

```
"Unknown chip model name 'Ampere(R) Altra(R) Processor'.
Please add new Windows on Arm SoC/chip support to arm/windows/init.c!"
```

---

**Previous error details:**

The error's reason was:

`woa_chip_name` (`windows-arm-init.h`)  enum had only 4 elements (stored in `woa_chip_name_last`)

```c
enum woa_chip_name {
	woa_chip_name_microsoft_sq_1 = 0,
	woa_chip_name_microsoft_sq_2 = 1,
	woa_chip_name_microsoft_sq_3 = 2,
	woa_chip_name_ampere_altra = 3,
	woa_chip_name_unknown = 4,
	woa_chip_name_last = woa_chip_name_unknown
};
```

However, `woa_chips[]`  (`init.c`) has a duplicated value for `woa_chip_name_microsoft_sq_3` due to different strings for same target after the [PR 220](#220)

> Strings are `Snapdragon (TM) 8cx Gen 3` and `Snapdragon Compute Platform`

And this was causing following `for loop` (`init.c`) is not checking for all elements in `woa_chips[]`.

```c
for (uint32_t i = 0; i < (uint32_t)woa_chip_name_last; i++) {
	size_t compare_length = wcsnlen(woa_chips[i].chip_name_string, CPUINFO_PACKAGE_NAME_MAX);
	int compare_result = wcsncmp(text_buffer, woa_chips[i].chip_name_string, compare_length);
	if (compare_result == 0) {
		chip_info = woa_chips + i;
		break;
	}
}
```

---

**Fix Details:**

We added `woa_chip_name_microsoft_sq_3_devkit` to maintain **one to one** relationship between `woa_chip_name` (`windows-arm-init.h`) and `woa_chips[]` (`init.c`).

Also, we especially specified indexes with `enums` to prevent future duplications and increase readability of the code and relationship.
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Fixing Ampere Altra Processor detection ozanMSFT/cpuinfo
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