Re: [PATCH v4 70/78] drm/vc4: hdmi: Always recenter the HDMI FIFO

Hi Maxime

On Wed, 8 Jul 2020 at 18:44, Maxime Ripard maxime@cerno.tech wrote:

In order to avoid a pixel getting stuck in an unflushable FIFO, we need to recenter the FIFO every time we're doing a modeset and not only if we're connected to an HDMI monitor.

Signed-off-by: Maxime Ripard maxime@cerno.tech

Reviewed-by: Dave Stevenson dave.stevenson@raspberrypi.com

---

drivers/gpu/drm/vc4/vc4_hdmi.c | 46 +++++++++++++++++++---------------- 1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index 4058985940e6..00592c1ada73 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -425,6 +425,30 @@ static void vc4_hdmi_set_timings(struct vc4_hdmi *vc4_hdmi, (hsync_pos ? 0 : VC4_HD_VID_CTL_HSYNC_LOW)); }

+static void vc4_hdmi_recenter_fifo(struct vc4_hdmi *vc4_hdmi) +{

•   u32 drift;
  

•   int ret;
  

•   drift = HDMI_READ(HDMI_FIFO_CTL);
  

•   drift &= VC4_HDMI_FIFO_VALID_WRITE_MASK;
  

•   HDMI_WRITE(HDMI_FIFO_CTL,
  

•              drift & ~VC4_HDMI_FIFO_CTL_RECENTER);
  

•   HDMI_WRITE(HDMI_FIFO_CTL,
  

•              drift | VC4_HDMI_FIFO_CTL_RECENTER);
  

•   usleep_range(1000, 1100);
  

•   HDMI_WRITE(HDMI_FIFO_CTL,
  

•              drift & ~VC4_HDMI_FIFO_CTL_RECENTER);
  

•   HDMI_WRITE(HDMI_FIFO_CTL,
  

•              drift | VC4_HDMI_FIFO_CTL_RECENTER);
  

•   ret = wait_for(HDMI_READ(HDMI_FIFO_CTL) &
  

•                  VC4_HDMI_FIFO_CTL_RECENTER_DONE, 1);
  

•   WARN_ONCE(ret, "Timeout waiting for "
  

•             "VC4_HDMI_FIFO_CTL_RECENTER_DONE");
  

+}

static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder) { struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode; @@ -543,8 +567,6 @@ static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder) }

    if (vc4_encoder->hdmi_monitor) {

•           u32 drift;
  

•           WARN_ON(!(HDMI_READ(HDMI_SCHEDULER_CONTROL) &
                      VC4_HDMI_SCHEDULER_CONTROL_HDMI_ACTIVE));
            HDMI_WRITE(HDMI_SCHEDULER_CONTROL,
  

@@ -555,25 +577,9 @@ static void vc4_hdmi_encoder_enable(struct drm_encoder *encoder) VC4_HDMI_RAM_PACKET_ENABLE);

            vc4_hdmi_set_infoframes(encoder);

•           drift = HDMI_READ(HDMI_FIFO_CTL);
  

•           drift &= VC4_HDMI_FIFO_VALID_WRITE_MASK;
  

•           HDMI_WRITE(HDMI_FIFO_CTL,
  

•                      drift & ~VC4_HDMI_FIFO_CTL_RECENTER);
  

•           HDMI_WRITE(HDMI_FIFO_CTL,
  

•                      drift | VC4_HDMI_FIFO_CTL_RECENTER);
  

•           usleep_range(1000, 1100);
  

•           HDMI_WRITE(HDMI_FIFO_CTL,
  

•                      drift & ~VC4_HDMI_FIFO_CTL_RECENTER);
  

•           HDMI_WRITE(HDMI_FIFO_CTL,
  

•                      drift | VC4_HDMI_FIFO_CTL_RECENTER);
  

•           ret = wait_for(HDMI_READ(HDMI_FIFO_CTL) &
  

•                          VC4_HDMI_FIFO_CTL_RECENTER_DONE, 1);
  

•           WARN_ONCE(ret, "Timeout waiting for "
  

•                     "VC4_HDMI_FIFO_CTL_RECENTER_DONE");
    }
  

•   vc4_hdmi_recenter_fifo(vc4_hdmi);
  

}

static enum drm_mode_status

git-series 0.9.1