drm/ast: Add support_wuxga flag to struct ast_device

Detect support for 1920x1200 (WUXGA) in ast_detect_widescreen(). The
flag is cleared by default. The test logic has been taken from existing
code in ast_crtc_helper_mode_valid(). The code in that function is being
replaced by the new flag.

v2:
- move shared detection code into helper (Jocelyn)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250131092257.115596-7-tzimmermann@suse.de

drivers/gpu/drm/ast/ast_drv.h

@@ -207,6 +207,7 @@ struct ast_device {
 
 	bool support_wsxga_p; /* 1680x1050 */
 	bool support_fullhd; /* 1920x1080 */
+	bool support_wuxga; /* 1920x1200 */
 
 	u8 *dp501_fw_addr;
 	const struct firmware *dp501_fw;	/* dp501 fw */

drivers/gpu/drm/ast/ast_main.c

@@ -49,14 +49,31 @@ static bool __ast_2100_detect_wsxga_p(struct ast_device *ast)
 	return false;
 }
 
+/* Try to detect WUXGA on Gen2+ */
+static bool __ast_2100_detect_wuxga(struct ast_device *ast)
+{
+	u8 vgacrd1;
+
+	if (ast->support_fullhd) {
+		vgacrd1 = ast_get_index_reg(ast, AST_IO_VGACRI, 0xd1);
+		if (!(vgacrd1 & AST_IO_VGACRD1_SUPPORTS_WUXGA))
+			return true;
+	}
+
+	return false;
+}
+
 static void ast_detect_widescreen(struct ast_device *ast)
 {
 	ast->support_wsxga_p = false;
 	ast->support_fullhd = false;
+	ast->support_wuxga = false;
 
 	if (AST_GEN(ast) >= 7) {
 		ast->support_wsxga_p = true;
 		ast->support_fullhd = true;
+		if (__ast_2100_detect_wuxga(ast))
+			ast->support_wuxga = true;
 	} else if (AST_GEN(ast) >= 6) {
 		if (__ast_2100_detect_wsxga_p(ast))
 			ast->support_wsxga_p = true;
@@ -64,6 +81,8 @@ static void ast_detect_widescreen(struct ast_device *ast)
 			ast->support_wsxga_p = true;
 		if (ast->support_wsxga_p)
 			ast->support_fullhd = true;
+		if (__ast_2100_detect_wuxga(ast))
+			ast->support_wuxga = true;
 	} else if (AST_GEN(ast) >= 5) {
 		if (__ast_2100_detect_wsxga_p(ast))
 			ast->support_wsxga_p = true;
@@ -71,6 +90,8 @@ static void ast_detect_widescreen(struct ast_device *ast)
 			ast->support_wsxga_p = true;
 		if (ast->support_wsxga_p)
 			ast->support_fullhd = true;
+		if (__ast_2100_detect_wuxga(ast))
+			ast->support_wuxga = true;
 	} else if (AST_GEN(ast) >= 4) {
 		if (__ast_2100_detect_wsxga_p(ast))
 			ast->support_wsxga_p = true;
@@ -78,6 +99,8 @@ static void ast_detect_widescreen(struct ast_device *ast)
 			ast->support_wsxga_p = true;
 		if (ast->support_wsxga_p)
 			ast->support_fullhd = true;
+		if (__ast_2100_detect_wuxga(ast))
+			ast->support_wuxga = true;
 	} else if (AST_GEN(ast) >= 3) {
 		if (__ast_2100_detect_wsxga_p(ast))
 			ast->support_wsxga_p = true;
@@ -85,6 +108,8 @@ static void ast_detect_widescreen(struct ast_device *ast)
 			if (ast->chip == AST2200)
 				ast->support_fullhd = true;
 		}
+		if (__ast_2100_detect_wuxga(ast))
+			ast->support_wuxga = true;
 	} else if (AST_GEN(ast) >= 2) {
 		if (__ast_2100_detect_wsxga_p(ast))
 			ast->support_wsxga_p = true;
@@ -92,6 +117,8 @@ static void ast_detect_widescreen(struct ast_device *ast)
 			if (ast->chip == AST2100)
 				ast->support_fullhd = true;
 		}
+		if (__ast_2100_detect_wuxga(ast))
+			ast->support_wuxga = true;
 	}
 }
 

drivers/gpu/drm/ast/ast_mode.c

@@ -1022,7 +1022,6 @@ ast_crtc_helper_mode_valid(struct drm_crtc *crtc, const struct drm_display_mode
 {
 	struct ast_device *ast = to_ast_device(crtc->dev);
 	enum drm_mode_status status;
-	uint32_t jtemp;
 
 	if (ast->support_wsxga_p) {
 		if ((mode->hdisplay == 1680) && (mode->vdisplay == 1050))
@@ -1041,11 +1040,10 @@ ast_crtc_helper_mode_valid(struct drm_crtc *crtc, const struct drm_display_mode
 				return MODE_OK;
 
 			if ((mode->hdisplay == 1920) && (mode->vdisplay == 1200)) {
-				jtemp = ast_get_index_reg_mask(ast, AST_IO_VGACRI, 0xd1, 0xff);
-				if (jtemp & 0x01)
-					return MODE_NOMODE;
-				else
+				if (ast->support_wuxga)
 					return MODE_OK;
+				else
+					return MODE_NOMODE;
 			}
 		}
 	}

drivers/gpu/drm/ast/ast_reg.h

@@ -55,6 +55,7 @@
 #define AST_IO_VGACRD1_TX_ANX9807_VBIOS		0x0a
 #define AST_IO_VGACRD1_TX_FW_EMBEDDED_FW	0x0c /* special case of DP501 */
 #define AST_IO_VGACRD1_TX_ASTDP			0x0e
+#define AST_IO_VGACRD1_SUPPORTS_WUXGA		BIT(0)
 
 #define AST_IO_VGACRD7_EDID_VALID_FLAG	BIT(0)
 #define AST_IO_VGACRDC_LINK_SUCCESS	BIT(0)