[PATCH v5 05/11] drm/bridge: it6505: bail out of the IRQ handler when status reads fail

[Daniel Golle]

When reading the interrupt status registers fails, the negative error
codes end up in int_status[], where it6505_test_bit() sees almost all
bits set: every interrupt sub-handler runs on garbage and the error
values are even written back to the status registers. Return IRQ_NONE
instead.

Fixes: b5c84a9edcd4 ("drm/bridge: add it6505 driver")
Signed-off-by: Daniel Golle <daniel@xxxxxxxxxxxxxx>
---
v5: new patch

 drivers/gpu/drm/bridge/ite-it6505.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 0f79ddfd1501..0e141310ed3c 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -2713,6 +2713,11 @@ static irqreturn_t it6505_int_threaded_handler(int unused, void *data)
 	int_status[1] = it6505_read(it6505, INT_STATUS_02);
 	int_status[2] = it6505_read(it6505, INT_STATUS_03);
 
+	if (int_status[0] < 0 || int_status[1] < 0 || int_status[2] < 0) {
+		pm_runtime_put_sync(dev);
+		return IRQ_NONE;
+	}
+
 	it6505_write(it6505, INT_STATUS_01, int_status[0]);
 	it6505_write(it6505, INT_STATUS_02, int_status[1]);
 	it6505_write(it6505, INT_STATUS_03, int_status[2]);
-- 
2.55.0