[O][PATCH 04/21] UBUNTU: SAUCE: media: qcom: camss: Fix ordering of pm_runtime_enable

[Juerg Haefliger]

From: Bryan O'Donoghue <bryan.odonoghue at linaro.org>

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.

The kernel log for this error looks like this:

qcom-camss ac5a000.camss: Failed to power up pipeline: -13

Fixes: 02afa816dbbf ("media: camss: Add basic runtime PM support")
Reported-by: Johan Hovold <johan+linaro at kernel.org>
Closes: https://lore.kernel.org/lkml/ZoVNHOTI0PKMNt4_@hovoldconsulting.com/
Tested-by: Johan Hovold <johan+linaro at kernel.org>
Cc: stable at vger.kernel.org
Signed-off-by: Bryan O'Donoghue <bryan.odonoghue at linaro.org>
Link: https://lore.kernel.org/lkml/ZoVNHOTI0PKMNt4_@hovoldconsulting.com/
Link: https://lore.kernel.org/r/20240729-linux-next-24-07-13-camss-fixes-v3-2-38235dc782c7@linaro.org
Signed-off-by: Johan Hovold <johan+linaro at kernel.org>
(cherry picked from commit a151766bd3688f6803e706c6433a7c8d3c6a6a94 linux-next)
Signed-off-by: Juerg Haefliger <juerg.haefliger at canonical.com>
---
 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);
 
-- 
2.43.0