We've had many silent hangs where the kernel would look like it just
stalled due to the access to one of the HDMI registers while the
controller was disabled.
Add a warning if we're about to do that so that it's at least not silent
anymore.
Signed-off-by: Maxime Ripard <max...@cerno.tech>
---
drivers/gpu/drm/vc4/vc4_hdmi_regs.h | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi_regs.h
b/drivers/gpu/drm/vc4/vc4_hdmi_regs.h
index 19d2fdc446bc..99dde6e06a37 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi_regs.h
+++ b/drivers/gpu/drm/vc4/vc4_hdmi_regs.h
@@ -1,6 +1,8 @@
#ifndef _VC4_HDMI_REGS_H_
#define _VC4_HDMI_REGS_H_
+#include <linux/pm_runtime.h>
+
#include "vc4_hdmi.h"
#define VC4_HDMI_PACKET_STRIDE 0x24
@@ -412,6 +414,8 @@ static inline u32 vc4_hdmi_read(struct vc4_hdmi *hdmi,
const struct vc4_hdmi_variant *variant = hdmi->variant;
void __iomem *base;
+ WARN_ON(!pm_runtime_active(&hdmi->pdev->dev));
+
if (reg >= variant->num_registers) {
dev_warn(&hdmi->pdev->dev,
"Invalid register ID %u\n", reg);
@@ -438,6 +442,8 @@ static inline void vc4_hdmi_write(struct vc4_hdmi *hdmi,
const struct vc4_hdmi_variant *variant = hdmi->variant;
void __iomem *base;
+ WARN_ON(!pm_runtime_active(&hdmi->pdev->dev));
+
if (reg >= variant->num_registers) {
dev_warn(&hdmi->pdev->dev,
"Invalid register ID %u\n", reg);
--
2.31.1
