[PATCH] drm/meson: Fix atomic mode switching regression

[Neil Armstrong]

Since commit 2bcd3ecab773 when switching mode from X11 (ubuntu mate for
example) the display gets blurry, looking like an invalid framebuffer width.

This commit fixed atomic crtc modesetting but didn't update the display
parameters when changing mode, but only when starting a mode setting after
a crtc disable.

This commit setups the crctc parameter in _begin() and _enable() to
take in account the current ctrc parameters.

Reported-by: Tony McKahan <tonymckahan@xxxxxxxxx>
Fixes: 2bcd3ecab773 ("drm/meson: Fixes for drm_crtc_vblank_on/off support")
Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
---
 drivers/gpu/drm/meson/meson_crtc.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/meson/meson_crtc.c b/drivers/gpu/drm/meson/meson_crtc.c
index 75d97f1b2e8f..5bb432021caf 100644
--- a/drivers/gpu/drm/meson/meson_crtc.c
+++ b/drivers/gpu/drm/meson/meson_crtc.c
@@ -82,14 +82,12 @@ static const struct drm_crtc_funcs meson_crtc_funcs = {
 
 };
 
-static void meson_crtc_enable(struct drm_crtc *crtc)
+static void meson_crtc_setup(struct drm_crtc *crtc)
 {
 	struct meson_crtc *meson_crtc = to_meson_crtc(crtc);
 	struct drm_crtc_state *crtc_state = crtc->state;
 	struct meson_drm *priv = meson_crtc->priv;
 
-	DRM_DEBUG_DRIVER("\n");
-
 	if (!crtc_state) {
 		DRM_ERROR("Invalid crtc_state\n");
 		return;
@@ -98,6 +96,16 @@ static void meson_crtc_enable(struct drm_crtc *crtc)
 	/* Enable VPP Postblend */
 	writel(crtc_state->mode.hdisplay,
 	       priv->io_base + _REG(VPP_POSTBLEND_H_SIZE));
+}
+
+static void meson_crtc_enable(struct drm_crtc *crtc)
+{
+	struct meson_crtc *meson_crtc = to_meson_crtc(crtc);
+	struct meson_drm *priv = meson_crtc->priv;
+
+	DRM_DEBUG_DRIVER("\n");
+
+	meson_crtc_setup(crtc);
 
 	/* VD1 Preblend vertical start/end */
 	writel(FIELD_PREP(GENMASK(11, 0), 2303),
@@ -121,6 +129,8 @@ static void meson_crtc_atomic_enable(struct drm_crtc *crtc,
 
 	if (!meson_crtc->enabled)
 		meson_crtc_enable(crtc);
+	else
+		meson_crtc_setup(crtc);
 
 	priv->viu.osd1_enabled = true;
 }
-- 
2.19.2