drm/vc4: hdmi: Always recenter the HDMI FIFO

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>
Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Tested-by: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://patchwork.freedesktop.org/patch/msgid/b3faaf05ac6c4d3c364d28fa441571eb85903269.1599120059.git-series.maxime@cerno.tech

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 3c7862a..c9eae53 100644 (file)
--- 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