From: Philippe CORNU <philippe.cornu@st.com>
Date: Thu, 1 Feb 2018 11:42:43 +0100
Subject: drm/stm: ltdc: remove non-alpha color formats on layer 2 for older hw
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Git-commit: 9569002a39cdc17b11f415f16215ec2428dad902
Patch-mainline: v4.17-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Hw older versions support non-alpha color formats derived
from native alpha color formats only on the primary layer.
For instance, RG16 native format without alpha works fine
on 2nd layer but XR24 (derived color format from AR24)
does not work on 2nd layer.

Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
Reviewed-by: Yannick Fertré <yannick.fertre@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180201104243.20726-3-philippe.cornu@st.com

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/stm/ltdc.c |   20 ++++++++++++++++++++
 drivers/gpu/drm/stm/ltdc.h |    1 +
 2 files changed, 21 insertions(+)

--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -703,6 +703,11 @@ static void ltdc_plane_atomic_update(str
 	if (!fb->format->has_alpha)
 		val = BF1_CA | BF2_1CA;
 
+	/* Manage hw-specific capabilities */
+	if (ldev->caps.non_alpha_only_l1 &&
+	    plane->type != DRM_PLANE_TYPE_PRIMARY)
+		val = BF1_PAXCA | BF2_1PAXCA;
+
 	reg_update_bits(ldev->regs, LTDC_L1BFCR + lofs,
 			LXBFCR_BF2 | LXBFCR_BF1, val);
 
@@ -785,6 +790,12 @@ static struct drm_plane *ltdc_plane_crea
 		drm_fmt_no_alpha = get_pixelformat_without_alpha(drm_fmt);
 		if (!drm_fmt_no_alpha)
 			continue;
+
+		/* Manage hw-specific capabilities */
+		if (ldev->caps.non_alpha_only_l1 &&
+		    type != DRM_PLANE_TYPE_PRIMARY)
+			continue;
+
 		formats[nb_fmt++] = drm_fmt_no_alpha;
 	}
 
@@ -913,10 +924,19 @@ static int ltdc_get_caps(struct drm_devi
 	case HWVER_10300:
 		ldev->caps.reg_ofs = REG_OFS_NONE;
 		ldev->caps.pix_fmt_hw = ltdc_pix_fmt_a0;
+		/*
+		 * Hw older versions support non-alpha color formats derived
+		 * from native alpha color formats only on the primary layer.
+		 * For instance, RG16 native format without alpha works fine
+		 * on 2nd layer but XR24 (derived color format from AR24)
+		 * does not work on 2nd layer.
+		 */
+		ldev->caps.non_alpha_only_l1 = true;
 		break;
 	case HWVER_20101:
 		ldev->caps.reg_ofs = REG_OFS_4;
 		ldev->caps.pix_fmt_hw = ltdc_pix_fmt_a1;
+		ldev->caps.non_alpha_only_l1 = false;
 		break;
 	default:
 		return -ENODEV;
--- a/drivers/gpu/drm/stm/ltdc.h
+++ b/drivers/gpu/drm/stm/ltdc.h
@@ -17,6 +17,7 @@ struct ltdc_caps {
 	u32 reg_ofs;		/* register offset for applicable regs */
 	u32 bus_width;		/* bus width (32 or 64 bits) */
 	const u32 *pix_fmt_hw;	/* supported pixel formats */
+	bool non_alpha_only_l1; /* non-native no-alpha formats on layer 1 */
 };
 
 struct ltdc_device {