Claude review: drm/tegra: gr2d/gr3d: Move pm_runtime_enable to gr*d_probe

Claude review: drm/tegra: gr2d/gr3d: Move pm_runtime_enable to gr*d_probe

[Claude Code Review Bot]

Overall Series Review

Subject: drm/tegra: gr2d/gr3d: Move pm_runtime_enable to gr*d_probe
Author: Svyatoslav Ryhel <clamor95@gmail.com>
Patches: 3
Reviewed: 2026-04-28T14:52:59.542322

---

This is a single-patch series that moves `pm_runtime_enable()`, `pm_runtime_use_autosuspend()`, and `pm_runtime_set_autosuspend_delay()` from the `gr*d_runtime_resume()` callbacks into `gr*d_probe()` for both gr2d and gr3d Tegra DRM drivers.

The fundamental change is **correct and desirable**. Calling `pm_runtime_enable()` from within a `runtime_resume` callback is wrong for two reasons:
1. It creates a chicken-and-egg problem — runtime PM must be enabled before `runtime_resume` can be invoked through normal paths, so on initial boot (without a prior sleep/resume cycle), runtime PM is never enabled.
2. On each subsequent resume, it calls `pm_runtime_enable()` again, decrementing `disable_depth` below zero, producing a kernel warning about an unbalanced enable.

Moving these calls to `probe()` properly pairs them with the `pm_runtime_disable()` already present in `gr*d_remove()`.

However, there is a **call ordering issue** that should be fixed before merging.

---

---
Generated by Claude Code Patch Reviewer

Claude review: drm/tegra: gr2d/gr3d: Move pm_runtime_enable to gr*d_probe

[Claude Code Review Bot]

Patch Review

**Issue: Wrong ordering of pm_runtime calls (moderate)**

In both gr2d and gr3d, the patch adds:

```c
pm_runtime_enable(dev);
pm_runtime_use_autosuspend(dev);
pm_runtime_set_autosuspend_delay(dev, 500);
```

The standard kernel pattern is the reverse — configure autosuspend *before* enabling runtime PM:

```c
pm_runtime_set_autosuspend_delay(dev, 500);
pm_runtime_use_autosuspend(dev);
pm_runtime_enable(dev);
```

Once `pm_runtime_enable()` is called, the runtime PM subsystem is live and can immediately attempt to suspend the device. If autosuspend isn't configured yet, there's a window where a `pm_runtime_put()` could trigger an immediate suspend rather than the intended 500ms delayed autosuspend. The delay should be set first, then autosuspend enabled, then finally runtime PM enabled.

This ordering issue existed in the original `runtime_resume` code too, but there it was less consequential since the device was already actively resuming. In `probe()`, with PM freshly enabled, it matters more.

**Observation: Placement relative to host1x_client_register (minor)**

The `pm_runtime_enable()` is placed after `host1x_client_register()`. If the host1x framework synchronously invokes `gr*d_init()` during registration, and that callback (or anything it triggers) does `pm_runtime_get_sync()`, the resume callback won't fire because runtime PM isn't enabled yet. In practice this is likely safe because `host1x_client_register` just adds the client to a list, but it's worth considering whether enabling PM before registration would be more robust. That would require adding `pm_runtime_disable()` to the error path for `host1x_client_register()` failure though.

**Observation: Missing Fixes tag**

If this addresses a real bug (runtime PM never properly enabled on first boot without a sleep/resume cycle), a `Fixes:` tag referencing the commit that originally placed `pm_runtime_enable` inside `runtime_resume` would help stable backport triage.

**Style nit: gr3d uses `&pdev->dev` vs gr2d uses `dev`**

In `gr2d_probe`, there's a local `struct device *dev = &pdev->dev;`, so the patch correctly uses `dev`. In `gr3d_probe`, there's no such local variable, so `&pdev->dev` is used. This is consistent with the existing code in each file — no issue, just noting the difference.

**Summary**: The change is correct in principle and fixes a real bug. Please reorder the three calls so `pm_runtime_enable()` comes last (after configuring autosuspend), and consider adding a `Fixes:` tag.

---
Generated by Claude Code Patch Reviewer

Claude review: drm/tegra: gr2d/gr3d: Move pm_runtime_enable to gr*d_probe

[Claude Code Review Bot]

Overall Series Review

Subject: drm/tegra: gr2d/gr3d: Move pm_runtime_enable to gr*d_probe
Author: Svyatoslav Ryhel <clamor95@gmail.com>
Patches: 4
Reviewed: 2026-05-05T08:41:52.459997

---

This is a well-motivated 2-patch series fixing power management issues in the Tegra GR2D/GR3D DRM drivers. The series makes two corrections:

1. Reorders address register map initialization before `host1x_client_register()` to close a theoretical race window.
2. Moves `pm_runtime_enable()` and autosuspend configuration from the runtime resume callback to `probe()`, and removes the corresponding PM teardown from `exit()`. This follows the standard Linux PM pattern and fixes a real resume malfunction.

The current upstream code has `pm_runtime_enable()` inside `gr*d_runtime_resume()`, which is architecturally wrong — runtime PM must be enabled before runtime resume can ever be called by the PM core. The only way this ever worked is through the `SET_SYSTEM_SLEEP_PM_OPS` path (`pm_runtime_force_resume`), and it breaks on the second system suspend/resume cycle because `pm_runtime_enable()` gets called with `disable_depth` already at 0, producing an "Unbalanced pm_runtime_enable!" warning and subsequent misbehavior.

Both patches are correct and the series is in a good state. One typo and one minor concern noted below. The Acked-by from Mikko Perttunen on patch 2 is a good sign.

**Series: Looks good with minor nits.**

---
Generated by Claude Code Patch Reviewer

[PATCH v3 0/2] drm/tegra: gr2d/gr3d: Move pm_runtime_enable to gr*d_probe

[Svyatoslav Ryhel]

The gr*d_remove() has pm_runtime_disable, this indicates it should be
paired with pm_runtime_enable in the probe instead of being inside
gr*d_runtime_resume().

---
Changes in v3:
- pm_runtime_enable moved before host1x_client_register

Changes in v2:
- remove pm from gr2d_exit along with pm from gr2d_runtime_resume
- move register map initialize before host1x_client_register
---

Ion Agorria (1):
  drm/tegra: gr2d/gr3d: Contain PM in the gr*d_probe/gr*d_remove

Svyatoslav Ryhel (1):
  drm/tegra: gr2d/gr3d: Initialize address register map before HOST1X
    client is registered

 drivers/gpu/drm/tegra/gr2d.c | 19 +++++++++----------
 drivers/gpu/drm/tegra/gr3d.c | 19 +++++++++----------
 2 files changed, 18 insertions(+), 20 deletions(-)

-- 
2.51.0

[PATCH v3 1/2] drm/tegra: gr2d/gr3d: Initialize address register map before HOST1X client is registered

[Svyatoslav Ryhel]

The host1x_client_register() function is called just prior to register map
initialization loop, making the device available to userspace. This may
result in userspace attempting to submits a job before the register map is
initialized. Address this by moving register initialization before host1x
client registration.

Acked-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
---
 drivers/gpu/drm/tegra/gr2d.c | 8 ++++----
 drivers/gpu/drm/tegra/gr3d.c | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/tegra/gr2d.c b/drivers/gpu/drm/tegra/gr2d.c
index 21f4dd0fa6af..e4148b034af7 100644
--- a/drivers/gpu/drm/tegra/gr2d.c
+++ b/drivers/gpu/drm/tegra/gr2d.c
@@ -276,16 +276,16 @@ static int gr2d_probe(struct platform_device *pdev)
 	if (err)
 		return err;
 
+	/* initialize address register map */
+	for (i = 0; i < ARRAY_SIZE(gr2d_addr_regs); i++)
+		set_bit(gr2d_addr_regs[i], gr2d->addr_regs);
+
 	err = host1x_client_register(&gr2d->client.base);
 	if (err < 0) {
 		dev_err(dev, "failed to register host1x client: %d\n", err);
 		return err;
 	}
 
-	/* initialize address register map */
-	for (i = 0; i < ARRAY_SIZE(gr2d_addr_regs); i++)
-		set_bit(gr2d_addr_regs[i], gr2d->addr_regs);
-
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/tegra/gr3d.c b/drivers/gpu/drm/tegra/gr3d.c
index 42e9656ab80c..47b0c6c56bfd 100644
--- a/drivers/gpu/drm/tegra/gr3d.c
+++ b/drivers/gpu/drm/tegra/gr3d.c
@@ -506,6 +506,10 @@ static int gr3d_probe(struct platform_device *pdev)
 	if (err)
 		return err;
 
+	/* initialize address register map */
+	for (i = 0; i < ARRAY_SIZE(gr3d_addr_regs); i++)
+		set_bit(gr3d_addr_regs[i], gr3d->addr_regs);
+
 	err = host1x_client_register(&gr3d->client.base);
 	if (err < 0) {
 		dev_err(&pdev->dev, "failed to register host1x client: %d\n",
@@ -513,10 +517,6 @@ static int gr3d_probe(struct platform_device *pdev)
 		return err;
 	}
 
-	/* initialize address register map */
-	for (i = 0; i < ARRAY_SIZE(gr3d_addr_regs); i++)
-		set_bit(gr3d_addr_regs[i], gr3d->addr_regs);
-
 	return 0;
 }
 
-- 
2.51.0

[PATCH v3 2/2] drm/tegra: gr2d/gr3d: Contain PM in the gr*d_probe/gr*d_remove

[Svyatoslav Ryhel]

From: Ion Agorria <ion@agorria.com>

The current power management configuration causes GR2G/GR3D to malfunction
after resume. Reconfigure all PM actions to be handled within the GR*D
probe and remove operations to address this.

Fixes: 62fa0a985e2c ("drm/tegra: Enable runtime PM during probe")
Acked-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Ion Agorria <ion@agorria.com>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
---
 drivers/gpu/drm/tegra/gr2d.c | 13 ++++++-------
 drivers/gpu/drm/tegra/gr3d.c | 13 ++++++-------
 2 files changed, 12 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/tegra/gr2d.c b/drivers/gpu/drm/tegra/gr2d.c
index e4148b034af7..892e3450b281 100644
--- a/drivers/gpu/drm/tegra/gr2d.c
+++ b/drivers/gpu/drm/tegra/gr2d.c
@@ -100,9 +100,6 @@ static int gr2d_exit(struct host1x_client *client)
 	if (err < 0)
 		return err;
 
-	pm_runtime_dont_use_autosuspend(client->dev);
-	pm_runtime_force_suspend(client->dev);
-
 	host1x_client_iommu_detach(client);
 	host1x_syncpt_put(client->syncpts[0]);
 	host1x_channel_put(gr2d->channel);
@@ -280,12 +277,18 @@ static int gr2d_probe(struct platform_device *pdev)
 	for (i = 0; i < ARRAY_SIZE(gr2d_addr_regs); i++)
 		set_bit(gr2d_addr_regs[i], gr2d->addr_regs);
 
+	pm_runtime_enable(dev);
+
 	err = host1x_client_register(&gr2d->client.base);
 	if (err < 0) {
+		pm_runtime_disable(dev);
 		dev_err(dev, "failed to register host1x client: %d\n", err);
 		return err;
 	}
 
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_set_autosuspend_delay(dev, 500);
+
 	return 0;
 }
 
@@ -367,10 +370,6 @@ static int __maybe_unused gr2d_runtime_resume(struct device *dev)
 		goto disable_clk;
 	}
 
-	pm_runtime_enable(dev);
-	pm_runtime_use_autosuspend(dev);
-	pm_runtime_set_autosuspend_delay(dev, 500);
-
 	return 0;
 
 disable_clk:
diff --git a/drivers/gpu/drm/tegra/gr3d.c b/drivers/gpu/drm/tegra/gr3d.c
index 47b0c6c56bfd..388e47943d5e 100644
--- a/drivers/gpu/drm/tegra/gr3d.c
+++ b/drivers/gpu/drm/tegra/gr3d.c
@@ -109,9 +109,6 @@ static int gr3d_exit(struct host1x_client *client)
 	if (err < 0)
 		return err;
 
-	pm_runtime_dont_use_autosuspend(client->dev);
-	pm_runtime_force_suspend(client->dev);
-
 	host1x_client_iommu_detach(client);
 	host1x_syncpt_put(client->syncpts[0]);
 	host1x_channel_put(gr3d->channel);
@@ -510,13 +507,19 @@ static int gr3d_probe(struct platform_device *pdev)
 	for (i = 0; i < ARRAY_SIZE(gr3d_addr_regs); i++)
 		set_bit(gr3d_addr_regs[i], gr3d->addr_regs);
 
+	pm_runtime_enable(&pdev->dev);
+
 	err = host1x_client_register(&gr3d->client.base);
 	if (err < 0) {
+		pm_runtime_disable(&pdev->dev);
 		dev_err(&pdev->dev, "failed to register host1x client: %d\n",
 			err);
 		return err;
 	}
 
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 500);
+
 	return 0;
 }
 
@@ -578,10 +581,6 @@ static int __maybe_unused gr3d_runtime_resume(struct device *dev)
 		goto disable_clk;
 	}
 
-	pm_runtime_enable(dev);
-	pm_runtime_use_autosuspend(dev);
-	pm_runtime_set_autosuspend_delay(dev, 500);
-
 	return 0;
 
 disable_clk:
-- 
2.51.0

Claude review: drm/tegra: gr2d/gr3d: Move pm_runtime_enable to gr*d_probe

[Claude Code Review Bot]

Overall Series Review

Subject: drm/tegra: gr2d/gr3d: Move pm_runtime_enable to gr*d_probe
Author: Svyatoslav Ryhel <clamor95@gmail.com>
Patches: 3
Reviewed: 2026-05-18T16:14:38.227738

---

This is a clean 2-patch series fixing power management lifecycle issues in the Tegra gr2d and gr3d DRM drivers. The changes are straightforward and well-motivated: patch 1 fixes a race between address register map initialization and userspace visibility, and patch 2 moves PM runtime enable/disable from the wrong callbacks (runtime_resume/client_exit) into probe/remove where they belong. The series has an Acked-by from Mikko Perttunen.

The series is correct and should fix the reported resume malfunction. I have a few minor observations but nothing blocking.

---
Generated by Claude Code Patch Reviewer

Claude review: drm/tegra: gr2d/gr3d: Initialize address register map before HOST1X client is registered

[Claude Code Review Bot]

Patch Review

**Assessment: Good, no issues.**

This patch moves the `set_bit` loop that populates `addr_regs` from after `host1x_client_register()` to before it, in both gr2d.c and gr3d.c. The rationale is sound: `host1x_client_register()` can make the device available to userspace, and `gr2d_is_addr_reg()`/`gr3d_is_addr_reg()` consult `addr_regs` during job submission validation. An uninitialized bitmap would fail to flag address registers, potentially allowing userspace to bypass address relocation checks.

The initialization depends only on the static `gr2d_addr_regs[]`/`gr3d_addr_regs[]` arrays and the already-allocated `gr2d->addr_regs`/`gr3d->addr_regs` bitmaps, so moving it earlier has no dependency issues.

The diff for both files is symmetric and minimal. No concerns.

---
Generated by Claude Code Patch Reviewer

Claude review: drm/tegra: gr2d/gr3d: Contain PM in the gr*d_probe/gr*d_remove

[Claude Code Review Bot]

Patch Review

**Assessment: Correct fix with minor observations.**

This patch makes two changes:

1. **Moves `pm_runtime_enable()`, `pm_runtime_use_autosuspend()`, and `pm_runtime_set_autosuspend_delay()` from `gr*d_runtime_resume()` into `gr*d_probe()`.** Having `pm_runtime_enable()` inside the runtime_resume callback was fundamentally wrong — the PM core needs runtime PM to be enabled *before* it can call the resume callback through normal runtime PM operations. Every resume would also redundantly re-configure autosuspend. Moving this to probe is correct.

2. **Removes `pm_runtime_dont_use_autosuspend()` and `pm_runtime_force_suspend()` from `gr*d_exit()`.** The exit callback no longer manages PM lifecycle; this is handled by `pm_runtime_disable()` in `gr*d_remove()`.

**Observations:**

- **Typo in commit message:** `"GR2G/GR3D"` should be `"GR2D/GR3D"`.

- **Ordering relative to other tegra drivers:** The patches place `pm_runtime_enable()` *before* `host1x_client_register()`, which is the safer ordering (avoids a race where userspace submits before PM is enabled). However, the sibling drivers `nvdec.c` and `vic.c` do the opposite — they call `host1x_client_register()` first, then `pm_runtime_enable()`. The new ordering in gr2d/gr3d is arguably more correct, but the inconsistency across the tegra driver family is worth being aware of.

- **Missing `pm_runtime_dont_use_autosuspend()` in remove:** The patch removes `pm_runtime_dont_use_autosuspend()` from `gr*d_exit()` but doesn't add it to `gr*d_remove()` before `pm_runtime_disable()`. The common pattern for drivers using autosuspend is to call `pm_runtime_dont_use_autosuspend()` then `pm_runtime_disable()` in the remove path, to cancel any pending autosuspend timer. In practice, `pm_runtime_disable()` handles cancellation internally, so this is not a bug — just a deviation from the typical pattern. The pre-existing `gr*d_remove()` also lacked it, so this is not a regression.

- **No explicit suspend on removal:** The original `gr*d_exit()` called `pm_runtime_force_suspend()` to ensure the hardware was powered down when the client was torn down. After this patch, if the device is runtime-active when `gr*d_remove()` is called, `pm_runtime_disable()` leaves it active — the clocks stay enabled until devm cleanup. This is acceptable for driver removal but is a minor change in teardown behavior worth noting.

- **Error path in probe:** The error path for `host1x_client_register()` failure correctly calls `pm_runtime_disable()`, which is good:
  ```c
  err = host1x_client_register(&gr2d->client.base);
  if (err < 0) {
      pm_runtime_disable(dev);
      ...
  }
  ```

Overall, this is a well-structured fix for a real resume regression. The minor items above are observations, not blockers.

---
Generated by Claude Code Patch Reviewer