target/linux/bcm27xx/patches-5.10/950-0602-drm-vc4-hdmi-Add-a-workqueue-to-set-scrambling.patch

   1 From c20cb28d802aa148cfa90c0682323e9d52dc0466 Mon Sep 17 00:00:00 2001
   2 From: Maxime Ripard <maxime@cerno.tech>
   3 Date: Fri, 7 May 2021 15:28:21 +0200
   4 Subject: [PATCH] drm/vc4: hdmi: Add a workqueue to set scrambling
   5
   6 It looks like some displays (like the LG 27UL850-W) don't enable the
   7 scrambling when the HDMI driver enables it. However, if we set later the
   8 scrambler enable bit, the display will work as expected.
   9
  10 Let's create delayed work queue to periodically look at the display
  11 scrambling status, and if it's not set yet try to enable it again.
  12
  13 Signed-off-by: Maxime Ripard <maxime@cerno.tech>
  14 ---
  15  drivers/gpu/drm/vc4/vc4_hdmi.c | 25 +++++++++++++++++++++++++
  16  drivers/gpu/drm/vc4/vc4_hdmi.h |  2 ++
  17  2 files changed, 27 insertions(+)
  18
  19 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
  20 +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
  21 @@ -538,6 +538,8 @@ static bool vc4_hdmi_supports_scrambling
  22         return true;
  23  }
  24
  25 +#define SCRAMBLING_POLLING_DELAY_MS    1000
  26 +
  27  static void vc4_hdmi_enable_scrambling(struct drm_encoder *encoder)
  28  {
  29         struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
  30 @@ -554,6 +556,9 @@ static void vc4_hdmi_enable_scrambling(s
  31
  32         HDMI_WRITE(HDMI_SCRAMBLER_CTL, HDMI_READ(HDMI_SCRAMBLER_CTL) |
  33                    VC5_HDMI_SCRAMBLER_CTL_ENABLE);
  34 +
  35 +       queue_delayed_work(system_wq, &vc4_hdmi->scrambling_work,
  36 +                          msecs_to_jiffies(SCRAMBLING_POLLING_DELAY_MS));
  37  }
  38
  39  static void vc4_hdmi_disable_scrambling(struct drm_encoder *encoder)
  40 @@ -572,6 +577,9 @@ static void vc4_hdmi_disable_scrambling(
  41         if (crtc && !vc4_hdmi_mode_needs_scrambling(&crtc->mode))
  42                 return;
  43
  44 +       if (delayed_work_pending(&vc4_hdmi->scrambling_work))
  45 +               cancel_delayed_work_sync(&vc4_hdmi->scrambling_work);
  46 +
  47         HDMI_WRITE(HDMI_SCRAMBLER_CTL, HDMI_READ(HDMI_SCRAMBLER_CTL) &
  48                    ~VC5_HDMI_SCRAMBLER_CTL_ENABLE);
  49
  50 @@ -579,6 +587,22 @@ static void vc4_hdmi_disable_scrambling(
  51         drm_scdc_set_high_tmds_clock_ratio(vc4_hdmi->ddc, false);
  52  }
  53
  54 +static void vc4_hdmi_scrambling_wq(struct work_struct *work)
  55 +{
  56 +       struct vc4_hdmi *vc4_hdmi = container_of(to_delayed_work(work),
  57 +                                                struct vc4_hdmi,
  58 +                                                scrambling_work);
  59 +
  60 +       if (drm_scdc_get_scrambling_status(vc4_hdmi->ddc))
  61 +               return;
  62 +
  63 +       drm_scdc_set_high_tmds_clock_ratio(vc4_hdmi->ddc, true);
  64 +       drm_scdc_set_scrambling(vc4_hdmi->ddc, true);
  65 +
  66 +       queue_delayed_work(system_wq, &vc4_hdmi->scrambling_work,
  67 +                          msecs_to_jiffies(SCRAMBLING_POLLING_DELAY_MS));
  68 +}
  69 +
  70  static void vc4_hdmi_encoder_post_crtc_disable(struct drm_encoder *encoder,
  71                                                struct drm_atomic_state *state)
  72  {
  73 @@ -2275,6 +2299,7 @@ static int vc4_hdmi_bind(struct device *
  74         vc4_hdmi = devm_kzalloc(dev, sizeof(*vc4_hdmi), GFP_KERNEL);
  75         if (!vc4_hdmi)
  76                 return -ENOMEM;
  77 +       INIT_DELAYED_WORK(&vc4_hdmi->scrambling_work, vc4_hdmi_scrambling_wq);
  78
  79         dev_set_drvdata(dev, vc4_hdmi);
  80         encoder = &vc4_hdmi->encoder.base.base;
  81 --- a/drivers/gpu/drm/vc4/vc4_hdmi.h
  82 +++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
  83 @@ -131,6 +131,8 @@ struct vc4_hdmi {
  84         struct vc4_hdmi_encoder encoder;
  85         struct drm_connector connector;
  86
  87 +       struct delayed_work scrambling_work;
  88 +
  89         struct i2c_adapter *ddc;
  90         void __iomem *hdmicore_regs;
  91         void __iomem *hd_regs;