Claude review: drm/msm/snapshot: fix dumping of the unaligned regions

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

Patch Review

**Debug filter left in — NAK as-is**

At line 187-188 of the patched file:
```c
if (strcmp(fmt, "dsi%d_ctrl"))
    return;
```
This is clearly debug scaffolding used during development to limit snapshot capture to only DSI controller blocks. `strcmp` returns non-zero (true) for any string that does NOT match `"dsi%d_ctrl"`, so this causes `msm_disp_snapshot_add_block()` to silently return without capturing any DPU, DP, or other display hardware blocks. This is a serious regression that must be removed.

**16x overallocation fix — correct**

The original code had:
```c
len_padded = aligned_len * REG_DUMP_ALIGN;
```
where `aligned_len` was already aligned to 16 bytes. This multiplied by 16 again, allocating 16x the needed memory. The fix correctly uses:
```c
len_padded = round_up(len, REG_DUMP_ALIGN);
```

**`DIV_ROUND_UP` for num_rows — correct**

Changing from `aligned_len / REG_DUMP_ALIGN` (which relied on pre-alignment) to `DIV_ROUND_UP(len, REG_DUMP_ALIGN)` correctly handles unaligned lengths by producing enough rows to cover the full region.

**`end_addr` tracking — correct**

Setting `end_addr = base_addr + len` (using the raw, unaligned length) ensures the per-register bounds checks in the dump loop:
```c
x0 = (addr < end_addr) ? readl_relaxed(addr + 0x0) : 0;
x4 = (addr + 0x4 < end_addr) ? readl_relaxed(addr + 0x4) : 0;
```
correctly avoid MMIO reads past the valid register region. This was already present in the pre-patch code but only works correctly now that `end_addr` uses the true length.

**Print tail handling — correct but minor style nit**

The new tail section in `msm_disp_state_print_regs` (lines 72-81):
```c
if (addr != end_addr) {
    drm_printf(p, "0x%lx : %08x",
               (unsigned long)(addr - base_addr),
               dump_addr[i * 4]);
    if (addr + 0x4 < end_addr)
        drm_printf(p, " %08x", dump_addr[i * 4 + 1]);
    if (addr + 0x8 < end_addr)
        drm_printf(p, " %08x", dump_addr[i * 4 + 2]);
    drm_printf(p, "\n");
}
```
The logic is correct: after printing full 4-register rows via `num_rows = len / REG_DUMP_ALIGN` (floor division), the tail handles the 1-3 remaining registers. The buffer accesses are safe because the dump function allocated `round_up(len, REG_DUMP_ALIGN)` bytes. One minor observation: the first register in the tail (`dump_addr[i * 4]`) is printed unconditionally — this is safe because the `addr != end_addr` guard ensures at least one register remains.

**Removing alignment from the caller — correct**

Changing `new_blk->size = ALIGN(len, REG_DUMP_ALIGN)` to `new_blk->size = len` moves alignment responsibility into the dump/print functions where it belongs. The raw length is needed to correctly bound MMIO reads and partial-row printing.

**Summary**: Remove the `strcmp(fmt, "dsi%d_ctrl")` debug filter and this patch is ready. The alignment fixes and tail-printing logic are sound.

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Generated by Claude Code Patch Reviewer