fix: remove hardcoded HSA_OVERRIDE_GFX_VERSION for RX 7000

[scarnago]

Problem

The current backend/app.py hardcodes HSA_OVERRIDE_GFX_VERSION=10.3.0, which is the value for RX 6000 series (RDNA 2).

On newer GPUs like the RX 7900 XTX (gfx1100, RDNA 3), this prevents ROCm 7.2+ from auto-detecting the correct architecture, causing GPU initialization issues.

Solution

Remove the hardcoded default. ROCm 7.2+ auto-detects gfx architecture natively.

Users with older GPUs can still set HSA_OVERRIDE_GFX_VERSION manually if needed.

Testing

Verified on Linux + ROCm 7.2.1 + RX 7900 XTX:

• Backend starts correctly
• Health endpoint reports: GPU: ROCm (Radeon RX 7900 XTX)

Impact

• Fixes: RX 7000 series (RDNA 3) support on Linux
• Preserves: Manual override still possible via env var
• Maintains: RX 6000 users can set HSA_OVERRIDE_GFX_VERSION=10.3.0 if needed

Summary by CodeRabbit

• Documentation

  • Clarified AMD GPU environment variable requirements and noted improved auto-detection support for newer ROCm systems.

• Changes

  • Removed unconditional defaulting of an AMD GPU environment variable; app now attempts safe auto-detection at startup and will leave settings unchanged if detection fails, requiring explicit configuration when needed.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 8c4a7e0 and 0085cb9.

📒 Files selected for processing (1)

• backend/app.py

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📝 Walkthrough

Walkthrough

The PR removes the unconditional HSA_OVERRIDE_GFX_VERSION fallback, documents AMD import-order for torch, and adds logic: if the env var is unset, run rocminfo, extract a gfx### token, convert it to a major.minor.patch string, and set HSA_OVERRIDE_GFX_VERSION; errors are ignored.

Changes

AMD GPU Configuration Documentation

Layer / File(s)	Summary
rocminfo-based HSA_OVERRIDE_GFX_VERSION detection backend/app.py	Removed unconditional HSA_OVERRIDE_GFX_VERSION="10.3.0" defaulting; added import-order documentation and conditional startup logic that runs rocminfo, regex-parses a gfx### value to construct a major.minor.patch string, and sets HSA_OVERRIDE_GFX_VERSION in os.environ when the variable was unset; detection errors are swallowed.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 I checked the air for gfx and name,
rocminfo whispered, I set the frame.
If numbers hide, I let it be,
Torch can start — or quietly free.
A hop, a sniff, environment in tune.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'fix: remove hardcoded HSA_OVERRIDE_GFX_VERSION for RX 7000' accurately summarizes the main change: removing a hardcoded GPU environment variable that was blocking RX 7000 GPU support.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

backend/app.py (1)

44-44: ⚡ Quick win

Split imports onto separate lines.

Per PEP 8 and Ruff E401, imports should be on separate lines for readability.

📦 Proposed fix

-        import subprocess, re
+        import re
+        import subprocess

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@backend/app.py` at line 44, The import statement "import subprocess, re"
should be split into separate lines to satisfy PEP 8 / Ruff E401; replace the
single combined import with two distinct imports (e.g., separate import
subprocess and import re) in backend/app.py where the current combined import
appears so each module is imported on its own line.

Source: Linters/SAST tools

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@backend/app.py`:
- Around line 52-55: The version-parsing code in backend/app.py currently uses
major.lstrip('0')/minor.lstrip('0')/patch.lstrip('0') which removes all leading
zeros incorrectly (e.g., "10" → "1"); change the logic to parse each slice as an
integer then convert back to string (e.g., int(major_slice) or 0) so gfx (the
gfx variable and the slices assigned to major/minor/patch) yields correct
version strings when building version in the version = f"...{...}.{...}.{...}"
expression; update the expressions that compute major, minor, patch and the
final version formation accordingly to use int(...) safely and fallback to 0.

---

Nitpick comments:
In `@backend/app.py`:
- Line 44: The import statement "import subprocess, re" should be split into
separate lines to satisfy PEP 8 / Ruff E401; replace the single combined import
with two distinct imports (e.g., separate import subprocess and import re) in
backend/app.py where the current combined import appears so each module is
imported on its own line.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: f738a63d-4e4c-4873-89b7-cc9b47b8da28

📥 Commits

Reviewing files that changed from the base of the PR and between 1cd05a3 and 8c4a7e0.

📒 Files selected for processing (1)

• backend/app.py