Claude review: drm/tyr: replace fixed sleeps with read_poll_timeout

[Claude Code Review Bot <claude-review@example.com>]

Patch Review

**Positive aspects:**
- Commit message is well-written with clear rationale and per-function timeout justification.
- The conversion correctly uses the `read_poll_timeout` API, matching its signature (`op`, `cond`, `sleep_delta`, `timeout_delta`).
- Error code change from `EIO` to `ETIMEDOUT` is appropriate (and the commit message correctly notes no callers inspect the specific error code).

**Issues:**

1. **Polling intervals differ from what landed upstream.** For `l2_power_on`, the patch uses:
   ```rust
   Delta::from_micros(100),
   Delta::from_millis(20),
   ```
   The commit message says this "matches the C panthor driver," which may be true for the C driver's values, but the version that landed in drm-next uses `Delta::from_millis(1)` / `Delta::from_millis(100)`. The 100µs poll interval is quite aggressive and may cause unnecessary CPU overhead on slow hardware. On the other hand, 20ms total timeout could be too tight for some platforms. The maintainer clearly chose more conservative values.

2. **`.map(|_| ())` pattern vs `?` + `Ok(())`.** The patch uses:
   ```rust
   .map(|_| ())
   .inspect_err(|_| dev_err!(dev, "soft reset timed out\n"))
   ```
   The version that landed uses the more idiomatic:
   ```rust
   .inspect_err(|_| dev_err!(dev, "GPU reset failed."))?;
   Ok(())
   ```
   The `.map(|_| ())` approach works but is slightly less clear than the `?` + `Ok(())` pattern, which makes the error propagation path more explicit and is a more common Rust idiom.

3. **Trailing `\n` in error messages.** The patch includes `\n` in `dev_err!` strings (e.g., `"soft reset timed out\n"`). The kernel `dev_err!` macro already appends a newline, so the explicit `\n` would result in a double newline. The landed version correctly omits it (e.g., `"GPU reset failed."`).

4. **Lost diagnostic information in `issue_soft_reset`.** The original code printed the raw register value on failure:
   ```rust
   dev_err!(dev, "GPU_INT_RAWSTAT is {}\n",
       regs::GPU_IRQ_RAWSTAT.read(dev, iomem)?
   );
   ```
   The patch replaces this with just `"soft reset timed out"`, losing useful debug information. While `read_poll_timeout` makes it harder to report the last polled value (since it's consumed internally), this is a minor regression in debuggability.

**Verdict:** The change itself is correct and addresses a real TODO. However, since this work has already landed in drm-next, this patch is moot. If it were being reviewed for merge, the main feedback would be: fix the double-newline issue, consider using `?` + `Ok(())` instead of `.map(|_| ())`, and verify the timeout values are appropriate for all supported platforms.

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