linux-kernel - [PATCH] drm/stm: ltdc: disable all layers before crtc shutdown

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Date:   Fri, 3 Jun 2022 15:41:51 +0200
From:   Yannick Fertre <yannick.fertre@...s.st.com>
To:     Yannick Fertre <yannick.fertre@...s.st.com>,
        Philippe Cornu <philippe.cornu@...s.st.com>,
        Raphael Gallais-Pou <raphael.gallais-pou@...s.st.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        <dri-devel@...ts.freedesktop.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH] drm/stm: ltdc: disable all layers before crtc shutdown

All plans must be disabled before the CRTC shutdown helping
the crtc to restart from a clean situation (without unwanted
planes already enable).

Signed-off-by: Yannick Fertre <yannick.fertre@...s.st.com>
---
 drivers/gpu/drm/stm/ltdc.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index 6bd45df8f5a7..eeefc3260c07 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -787,11 +787,17 @@ static void ltdc_crtc_atomic_disable(struct drm_crtc *crtc,
 {
 	struct ltdc_device *ldev = crtc_to_ltdc(crtc);
 	struct drm_device *ddev = crtc->dev;
+	int layer_index = 0;
 
 	DRM_DEBUG_DRIVER("\n");
 
 	drm_crtc_vblank_off(crtc);
 
+	/* Disable all layers */
+	for (layer_index = 0; layer_index < ldev->caps.nb_layers; layer_index++)
+		regmap_write_bits(ldev->regmap, LTDC_L1CR + layer_index * LAY_OFS,
+				  LXCR_CLUTEN | LXCR_LEN, 0);
+
 	/* disable IRQ */
 	regmap_clear_bits(ldev->regmap, LTDC_IER, IER_RRIE | IER_FUIE | IER_TERRIE);
 
-- 
2.25.1