Hi Maxime
Thanks for the patch.
On Fri, 7 May 2021 at 16:06, Maxime Ripard <maxime@xxxxxxxxxx> wrote:
>
> It looks like some displays (like the LG 27UL850-W) don't enable the
> scrambling when the HDMI driver enables it. However, if we set later the
> scrambler enable bit, the display will work as expected.
>
> Let's create delayed work queue to periodically look at the display
> scrambling status, and if it's not set yet try to enable it again.
>
> Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
Reviewed-by: Dave Stevenson <dave.stevenson@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/vc4/vc4_hdmi.c | 25 +++++++++++++++++++++++++
> drivers/gpu/drm/vc4/vc4_hdmi.h | 2 ++
> 2 files changed, 27 insertions(+)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index bda12fea0dce..4fa7ea419594 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -482,6 +482,8 @@ static bool vc4_hdmi_supports_scrambling(struct drm_encoder *encoder,
> return true;
> }
>
> +#define SCRAMBLING_POLLING_DELAY_MS 1000
> +
> static void vc4_hdmi_enable_scrambling(struct drm_encoder *encoder)
> {
> struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
> @@ -498,6 +500,9 @@ static void vc4_hdmi_enable_scrambling(struct drm_encoder *encoder)
>
> HDMI_WRITE(HDMI_SCRAMBLER_CTL, HDMI_READ(HDMI_SCRAMBLER_CTL) |
> VC5_HDMI_SCRAMBLER_CTL_ENABLE);
> +
> + queue_delayed_work(system_wq, &vc4_hdmi->scrambling_work,
> + msecs_to_jiffies(SCRAMBLING_POLLING_DELAY_MS));
> }
>
> static void vc4_hdmi_disable_scrambling(struct drm_encoder *encoder)
> @@ -516,6 +521,9 @@ static void vc4_hdmi_disable_scrambling(struct drm_encoder *encoder)
> if (crtc && !vc4_hdmi_mode_needs_scrambling(&crtc->mode))
> return;
>
> + if (delayed_work_pending(&vc4_hdmi->scrambling_work))
> + cancel_delayed_work_sync(&vc4_hdmi->scrambling_work);
> +
> HDMI_WRITE(HDMI_SCRAMBLER_CTL, HDMI_READ(HDMI_SCRAMBLER_CTL) &
> ~VC5_HDMI_SCRAMBLER_CTL_ENABLE);
>
> @@ -523,6 +531,22 @@ static void vc4_hdmi_disable_scrambling(struct drm_encoder *encoder)
> drm_scdc_set_high_tmds_clock_ratio(vc4_hdmi->ddc, false);
> }
>
> +static void vc4_hdmi_scrambling_wq(struct work_struct *work)
> +{
> + struct vc4_hdmi *vc4_hdmi = container_of(to_delayed_work(work),
> + struct vc4_hdmi,
> + scrambling_work);
> +
> + if (drm_scdc_get_scrambling_status(vc4_hdmi->ddc))
> + return;
> +
> + drm_scdc_set_high_tmds_clock_ratio(vc4_hdmi->ddc, true);
> + drm_scdc_set_scrambling(vc4_hdmi->ddc, true);
> +
> + queue_delayed_work(system_wq, &vc4_hdmi->scrambling_work,
> + msecs_to_jiffies(SCRAMBLING_POLLING_DELAY_MS));
> +}
> +
> static void vc4_hdmi_encoder_post_crtc_disable(struct drm_encoder *encoder,
> struct drm_atomic_state *state)
> {
> @@ -2031,6 +2055,7 @@ static int vc4_hdmi_bind(struct device *dev, struct device *master, void *data)
> vc4_hdmi = devm_kzalloc(dev, sizeof(*vc4_hdmi), GFP_KERNEL);
> if (!vc4_hdmi)
> return -ENOMEM;
> + INIT_DELAYED_WORK(&vc4_hdmi->scrambling_work, vc4_hdmi_scrambling_wq);
>
> dev_set_drvdata(dev, vc4_hdmi);
> encoder = &vc4_hdmi->encoder.base.base;
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.h b/drivers/gpu/drm/vc4/vc4_hdmi.h
> index 3cd021136402..00efcf291c5a 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.h
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.h
> @@ -126,6 +126,8 @@ struct vc4_hdmi {
> struct vc4_hdmi_encoder encoder;
> struct drm_connector connector;
>
> + struct delayed_work scrambling_work;
> +
> struct i2c_adapter *ddc;
> void __iomem *hdmicore_regs;
> void __iomem *hd_regs;
> --
> 2.31.1
>
