[PATCH] media: rkvdec: fix PM runtime teardown ordering in remove

[Francesco Saverio Pavone <pavone.lawyer@gmail.com>]

From: Jonas Karlman <jonas@kwiboo.se>

The current remove() path calls rkvdec_v4l2_cleanup() and
pm_runtime_disable() before pm_runtime_dont_use_autosuspend(), and
frees the empty IOMMU domain after that. With autosuspend still
armed when the domain goes away, the VDPU381 can be left in a dirty
state across module reload and suspend/resume cycles.

On RK3588 this surfaces as a VP9 inter-prediction bug: from the
second ALTREF frame onward, motion blocks decode with U=V=0 (BT.709
green), while intra and static blocks stay correct. Reordering the
teardown to dont_use_autosuspend() -> iommu_domain_free() ->
pm_runtime_disable() -> v4l2_cleanup() makes the symptom go away.

Tested on a Radxa Rock 5B+ (RK3588, 8 GB LPDDR5) with both the
libva-v4l2-request mpv pipeline and Chromium's V4L2 stateless
decoder. With the fix, 300 random pixel samples on VP9 Profile 0
clips at 1080p and 1440p match a libvpx software reference exactly
(worst delta 0). Without it, the same 1080p sample at frame 4,
pixel (960, 270) reads HW=(0,112,0) vs SW=(204,147,116). HEVC and
H.264 stateless decoding via mpv keep running on hardware with no
fallback.

Fixes: ff8c5622f9f7 ("media: rkvdec: Restore iommu addresses on errors")
Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Tested-by: Francesco Saverio Pavone <pavone.lawyer@gmail.com>
Signed-off-by: Francesco Saverio Pavone <pavone.lawyer@gmail.com>
---
 drivers/media/platform/rockchip/rkvdec/rkvdec.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/rockchip/rkvdec/rkvdec.c b/drivers/media/platform/rockchip/rkvdec/rkvdec.c
index 6f5f0422d317..bb95b090a25b 100644
--- a/drivers/media/platform/rockchip/rkvdec/rkvdec.c
+++ b/drivers/media/platform/rockchip/rkvdec/rkvdec.c
@@ -2066,12 +2066,13 @@ static void rkvdec_remove(struct platform_device *pdev)
 
 	cancel_delayed_work_sync(&rkvdec->watchdog_work);
 
-	rkvdec_v4l2_cleanup(rkvdec);
-	pm_runtime_disable(&pdev->dev);
 	pm_runtime_dont_use_autosuspend(&pdev->dev);
 
 	if (rkvdec->empty_domain)
 		iommu_domain_free(rkvdec->empty_domain);
+
+	pm_runtime_disable(&pdev->dev);
+	rkvdec_v4l2_cleanup(rkvdec);
 }
 
 #ifdef CONFIG_PM
-- 
2.45.0