target/linux/bcm27xx/patches-5.10/950-0671-drm-vc4-hdmi-Warn-if-we-access-the-controller-while-.patch

   1 From f67dbf74cc7bce6d85b7c4b5b917c30f2dfc2626 Mon Sep 17 00:00:00 2001
   2 From: Maxime Ripard <maxime@cerno.tech>
   3 Date: Mon, 5 Jul 2021 10:32:30 +0200
   4 Subject: [PATCH] drm/vc4: hdmi: Warn if we access the controller while
   5  disabled
   6
   7 We've had many silent hangs where the kernel would look like it just
   8 stalled due to the access to one of the HDMI registers while the
   9 controller was disabled.
  10
  11 Add a warning if we're about to do that so that it's at least not silent
  12 anymore.
  13
  14 Signed-off-by: Maxime Ripard <maxime@cerno.tech>
  15 ---
  16  drivers/gpu/drm/vc4/vc4_hdmi_regs.h | 6 ++++++
  17  1 file changed, 6 insertions(+)
  18
  19 --- a/drivers/gpu/drm/vc4/vc4_hdmi_regs.h
  20 +++ b/drivers/gpu/drm/vc4/vc4_hdmi_regs.h
  21 @@ -1,6 +1,8 @@
  22  #ifndef _VC4_HDMI_REGS_H_
  23  #define _VC4_HDMI_REGS_H_
  24
  25 +#include <linux/pm_runtime.h>
  26 +
  27  #include "vc4_hdmi.h"
  28
  29  #define VC4_HDMI_PACKET_STRIDE                 0x24
  30 @@ -412,6 +414,8 @@ static inline u32 vc4_hdmi_read(struct v
  31         const struct vc4_hdmi_variant *variant = hdmi->variant;
  32         void __iomem *base;
  33
  34 +       WARN_ON(!pm_runtime_active(&hdmi->pdev->dev));
  35 +
  36         if (reg >= variant->num_registers) {
  37                 dev_warn(&hdmi->pdev->dev,
  38                          "Invalid register ID %u\n", reg);
  39 @@ -438,6 +442,8 @@ static inline void vc4_hdmi_write(struct
  40         const struct vc4_hdmi_variant *variant = hdmi->variant;
  41         void __iomem *base;
  42
  43 +       WARN_ON(!pm_runtime_active(&hdmi->pdev->dev));
  44 +
  45         if (reg >= variant->num_registers) {
  46                 dev_warn(&hdmi->pdev->dev,
  47                          "Invalid register ID %u\n", reg);