[PATCH 2/4] dmaengine: ste_dma40: Fix probe runtime PM disable

[Linus Walleij <linusw@kernel.org>]

d40_probe() can jump to destroy_cache before runtime PM has been enabled
for the DMA controller device. Calling pm_runtime_disable() on that path
increments disable_depth, which can leave runtime PM disabled after a later
successful deferred probe.

Track whether this probe attempt enabled runtime PM before disabling it on
the error path.

Reported-by: sashiko-bot@kernel.org
Closes: https://lore.kernel.org/dmaengine/20260618051539.15E201F000E9@smtp.kernel.org/
Assisted-by: Codex:gpt-5-5
Signed-off-by: Linus Walleij <linusw@kernel.org>
---
 drivers/dma/ste_dma40.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index d5837aa0a789..0c8ff299c2c2 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -3502,6 +3502,7 @@ static int __init d40_probe(struct platform_device *pdev)
 	struct resource *res;
 	struct resource res_lcpa;
 	int num_reserved_chans;
+	bool runtime_pm_enabled = false;
 	u32 val;
 	int ret;
 
@@ -3623,6 +3624,7 @@ static int __init d40_probe(struct platform_device *pdev)
 	pm_runtime_mark_last_busy(base->dev);
 	pm_runtime_set_active(base->dev);
 	pm_runtime_enable(base->dev);
+	runtime_pm_enabled = true;
 
 	ret = d40_dmaengine_init(base, num_reserved_chans);
 	if (ret)
@@ -3658,7 +3660,8 @@ static int __init d40_probe(struct platform_device *pdev)
 		regulator_disable(base->lcpa_regulator);
 		regulator_put(base->lcpa_regulator);
 	}
-	pm_runtime_disable(base->dev);
+	if (runtime_pm_enabled)
+		pm_runtime_disable(base->dev);
 
  report_failure:
 	d40_err(dev, "probe failed\n");

-- 
2.55.0