[PATCH 2/2] media: qcom: camss: Fix ordering of pm_runtime_enable

From: Bryan O'Donoghue
Date: Sun Jul 14 2024 - 18:54:21 EST


pm_runtime_enable() should happen prior to vfe_get() since vfe_get() calls
pm_runtime_resume_and_get().

This is a basic race condition that doesn't show up for most users so is
not widely reported. If you blacklist qcom-camss in modules.d and then
subsequently modprobe the module post-boot it is possible to reliably show
this error up.

Fixes: 02afa816dbbf ("media: camss: Add basic runtime PM support")
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
---
drivers/media/platform/qcom/camss/camss.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/qcom/camss/camss.c b/drivers/media/platform/qcom/camss/camss.c
index 51b1d3550421..d64985ca6e88 100644
--- a/drivers/media/platform/qcom/camss/camss.c
+++ b/drivers/media/platform/qcom/camss/camss.c
@@ -2283,6 +2283,8 @@ static int camss_probe(struct platform_device *pdev)

v4l2_async_nf_init(&camss->notifier, &camss->v4l2_dev);

+ pm_runtime_enable(dev);
+
num_subdevs = camss_of_parse_ports(camss);
if (num_subdevs < 0) {
ret = num_subdevs;
@@ -2323,8 +2325,6 @@ static int camss_probe(struct platform_device *pdev)
}
}

- pm_runtime_enable(dev);
-
return 0;

err_register_subdevs:
@@ -2332,6 +2332,7 @@ static int camss_probe(struct platform_device *pdev)
err_v4l2_device_unregister:
v4l2_device_unregister(&camss->v4l2_dev);
v4l2_async_nf_cleanup(&camss->notifier);
+ pm_runtime_disable(dev);
err_genpd_cleanup:
camss_genpd_cleanup(camss);


--
2.45.2