linux-kernel - [PATCH 1/7] drm/mcde: Provide vblank handling unconditionally

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Message-Id: <20191106165835.2863-2-stephan@gerhold.net>
Date:   Wed,  6 Nov 2019 17:58:29 +0100
From:   Stephan Gerhold <stephan@...hold.net>
To:     Linus Walleij <linus.walleij@...aro.org>
Cc:     David Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Stephan Gerhold <stephan@...hold.net>
Subject: [PATCH 1/7] drm/mcde: Provide vblank handling unconditionally

At the moment, vblank handling is only enabled together with
TE synchronization. However, the vblank IRQ is also working with
on displays without TE synchronization (e.g. DSI video mode panels).
It seems like the vblank IRQ is actually generated by the
MCDE hardware for the channel.

Therefore, the vblank handling should be working correctly in
all the cases and we can enable it unconditionally.

Signed-off-by: Stephan Gerhold <stephan@...hold.net>
---
 drivers/gpu/drm/mcde/mcde_display.c | 15 +++++----------
 drivers/gpu/drm/mcde/mcde_drv.c     | 16 ++++------------
 2 files changed, 9 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/mcde/mcde_display.c b/drivers/gpu/drm/mcde/mcde_display.c
index 751454ae3cd1..65522481b367 100644
--- a/drivers/gpu/drm/mcde/mcde_display.c
+++ b/drivers/gpu/drm/mcde/mcde_display.c
@@ -934,10 +934,10 @@ static void mcde_display_enable(struct drm_simple_display_pipe *pipe,
 		val = readl(mcde->regs + MCDE_CRC);
 		val |= MCDE_CRC_SYCEN0;
 		writel(val, mcde->regs + MCDE_CRC);
-
-		drm_crtc_vblank_on(crtc);
 	}
 
+	drm_crtc_vblank_on(crtc);
+
 	dev_info(drm->dev, "MCDE display is enabled\n");
 }
 
@@ -947,8 +947,7 @@ static void mcde_display_disable(struct drm_simple_display_pipe *pipe)
 	struct drm_device *drm = crtc->dev;
 	struct mcde *mcde = drm->dev_private;
 
-	if (mcde->te_sync)
-		drm_crtc_vblank_off(crtc);
+	drm_crtc_vblank_off(crtc);
 
 	/* Disable FIFO A flow */
 	mcde_disable_fifo(mcde, MCDE_FIFO_A, true);
@@ -1097,6 +1096,8 @@ static struct drm_simple_display_pipe_funcs mcde_display_funcs = {
 	.enable = mcde_display_enable,
 	.disable = mcde_display_disable,
 	.update = mcde_display_update,
+	.enable_vblank = mcde_display_enable_vblank,
+	.disable_vblank = mcde_display_disable_vblank,
 	.prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
 };
 
@@ -1123,12 +1124,6 @@ int mcde_display_init(struct drm_device *drm)
 		DRM_FORMAT_YUV422,
 	};
 
-	/* Provide vblank only when we have TE enabled */
-	if (mcde->te_sync) {
-		mcde_display_funcs.enable_vblank = mcde_display_enable_vblank;
-		mcde_display_funcs.disable_vblank = mcde_display_disable_vblank;
-	}
-
 	ret = drm_simple_display_pipe_init(drm, &mcde->pipe,
 					   &mcde_display_funcs,
 					   formats, ARRAY_SIZE(formats),
diff --git a/drivers/gpu/drm/mcde/mcde_drv.c b/drivers/gpu/drm/mcde/mcde_drv.c
index 5649887d2b90..0ccd3b0308c2 100644
--- a/drivers/gpu/drm/mcde/mcde_drv.c
+++ b/drivers/gpu/drm/mcde/mcde_drv.c
@@ -179,18 +179,10 @@ static int mcde_modeset_init(struct drm_device *drm)
 	mode_config->min_height = 1;
 	mode_config->max_height = 1080;
 
-	/*
-	 * Currently we only support vblank handling on the DSI bridge, using
-	 * TE synchronization. If TE sync is not set up, it is still possible
-	 * to push out a single update on demand, but this is hard for DRM to
-	 * exploit.
-	 */
-	if (mcde->te_sync) {
-		ret = drm_vblank_init(drm, 1);
-		if (ret) {
-			dev_err(drm->dev, "failed to init vblank\n");
-			goto out_config;
-		}
+	ret = drm_vblank_init(drm, 1);
+	if (ret) {
+		dev_err(drm->dev, "failed to init vblank\n");
+		goto out_config;
 	}
 
 	ret = mcde_display_init(drm);
-- 
2.23.0