From c1cbdc9f1528eee4dabe4f908aea107c753fac0c Mon Sep 17 00:00:00 2001
From: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Date: Mon, 26 Aug 2024 15:30:54 +0200
Subject: [PATCH] media: pisp_be: Fix pm_runtime underrun in probe

During the probe() routine, the PiSP BE driver needs to power up the
interface in order to identify and initialize the hardware.

The driver resumes the interface by calling the
pispbe_runtime_resume() function directly, without going
through the pm_runtime helpers, but later suspends it by calling
pm_runtime_put_autosuspend().

This causes a PM usage count imbalance at probe time, notified by the
runtime_pm framework with the below message in the system log:

 pispbe 1000880000.pisp_be: Runtime PM usage count underflow!

Fix this by resuming the interface using the pm runtime helpers instead
of calling the resume function directly and use the pm_runtime framework
in the probe() error path. While at it, remove manual suspend of the
interface in the remove() function. The driver cannot be unloaded if in
use, so simply disable runtime pm.

To simplify the implementation, make the driver depend on PM as the
RPI5 platform where the ISP is integrated in uses the PM framework by
default.

Fixes: 12187bd5d4f8 ("media: raspberrypi: Add support for PiSP BE")
Cc: stable@vger.kernel.org
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
---
 drivers/media/platform/raspberrypi/pisp_be/Kconfig | 1 +
 1 file changed, 1 insertion(+)

--- a/drivers/media/platform/raspberrypi/pisp_be/Kconfig
+++ b/drivers/media/platform/raspberrypi/pisp_be/Kconfig
@@ -2,6 +2,7 @@ config VIDEO_RASPBERRYPI_PISP_BE
 	tristate "Raspberry Pi PiSP Backend (BE) ISP driver"
 	depends on V4L_PLATFORM_DRIVERS
 	depends on VIDEO_DEV
+	depends on PM
 	depends on ARCH_BCM2835 || COMPILE_TEST
 	depends on PM
 	select VIDEO_V4L2_SUBDEV_API
