[PATCH] drm/exynos: g2d: fix autosuspend cleanup on probe failure

[Guangshuo Li <lgs201920130244@gmail.com>]

g2d_probe() calls pm_runtime_use_autosuspend(), but its failure path
does not call the matching pm_runtime_dont_use_autosuspend() before
disabling runtime PM.

If the autosuspend delay is set to a negative value while autosuspend
is enabled, the runtime PM core increments usage_count to prevent
runtime suspend. Without calling pm_runtime_dont_use_autosuspend()
during cleanup, this reference is not dropped and usage_count remains
unbalanced.

The documentation for pm_runtime_use_autosuspend() also notes that it
is important to undo it with pm_runtime_dont_use_autosuspend() at
driver exit time, unless runtime PM was initially enabled with
devm_pm_runtime_enable().

Add the missing pm_runtime_dont_use_autosuspend() call to the probe
failure path before disabling runtime PM.

This issue was found by manual code inspection.

Fixes: d7f1642c90ab ("drm/exynos: add G2D driver")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/gpu/drm/exynos/exynos_drm_g2d.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_g2d.c b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
index e92a4d872c41..98a5679258e2 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_g2d.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_g2d.c
@@ -1523,6 +1523,7 @@ static int g2d_probe(struct platform_device *pdev)
 	return 0;
 
 err_put_clk:
+	pm_runtime_dont_use_autosuspend(dev);
 	pm_runtime_disable(dev);
 err_destroy_workqueue:
 	destroy_workqueue(g2d->g2d_workq);
-- 
2.43.0