drm/ast: Add support_fullhd flag to struct ast_device

Detect support for 1920x1080 (FullHD) 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.

For Gen3, a new branch duplicates the Gen2 logic and adds a test for
AST2200. Gen2 adds a test for AST2100.

v2:
- use fullhd flag for setting max width/height

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250131092257.115596-6-tzimmermann@suse.de

3 files changed, 22 insertions, 10 deletions

diff --git a/drivers/gpu/drm/ast/ast_drv.h b/drivers/gpu/drm/ast/ast_drv.h
index ec5b204be1da..01ef0c0d5db7 100644
--- a/drivers/gpu/drm/ast/ast_drv.h
+++ b/drivers/gpu/drm/ast/ast_drv.h
@@ -206,6 +206,7 @@ struct ast_device {
 	} output;
 
 	bool support_wsxga_p; /* 1680x1050 */
+	bool support_fullhd; /* 1920x1080 */
 
 	u8 *dp501_fw_addr;
 	const struct firmware *dp501_fw;	/* dp501 fw */
diff --git a/drivers/gpu/drm/ast/ast_main.c b/drivers/gpu/drm/ast/ast_main.c
index 93ae9a275c96..6e964a0714b4 100644
--- a/drivers/gpu/drm/ast/ast_main.c
+++ b/drivers/gpu/drm/ast/ast_main.c
@@ -52,27 +52,46 @@ static bool __ast_2100_detect_wsxga_p(struct ast_device *ast)
 static void ast_detect_widescreen(struct ast_device *ast)
 {
 	ast->support_wsxga_p = false;
+	ast->support_fullhd = false;
 
 	if (AST_GEN(ast) >= 7) {
 		ast->support_wsxga_p = true;
+		ast->support_fullhd = true;
 	} else if (AST_GEN(ast) >= 6) {
 		if (__ast_2100_detect_wsxga_p(ast))
 			ast->support_wsxga_p = true;
 		else if (ast->chip == AST2510)
 			ast->support_wsxga_p = true;
+		if (ast->support_wsxga_p)
+			ast->support_fullhd = true;
 	} else if (AST_GEN(ast) >= 5) {
 		if (__ast_2100_detect_wsxga_p(ast))
 			ast->support_wsxga_p = true;
 		else if (ast->chip == AST1400)
 			ast->support_wsxga_p = true;
+		if (ast->support_wsxga_p)
+			ast->support_fullhd = true;
 	} else if (AST_GEN(ast) >= 4) {
 		if (__ast_2100_detect_wsxga_p(ast))
 			ast->support_wsxga_p = true;
 		else if (ast->chip == AST1300)
 			ast->support_wsxga_p = true;
+		if (ast->support_wsxga_p)
+			ast->support_fullhd = true;
+	} else if (AST_GEN(ast) >= 3) {
+		if (__ast_2100_detect_wsxga_p(ast))
+			ast->support_wsxga_p = true;
+		if (ast->support_wsxga_p) {
+			if (ast->chip == AST2200)
+				ast->support_fullhd = true;
+		}
 	} else if (AST_GEN(ast) >= 2) {
 		if (__ast_2100_detect_wsxga_p(ast))
 			ast->support_wsxga_p = true;
+		if (ast->support_wsxga_p) {
+			if (ast->chip == AST2100)
+				ast->support_fullhd = true;
+		}
 	}
 }
 
diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
index d1b3136b3769..dda2c4fb0a48 100644
--- a/drivers/gpu/drm/ast/ast_mode.c
+++ b/drivers/gpu/drm/ast/ast_mode.c
@@ -1036,10 +1036,7 @@ ast_crtc_helper_mode_valid(struct drm_crtc *crtc, const struct drm_display_mode
 		if ((mode->hdisplay == 1600) && (mode->vdisplay == 900))
 			return MODE_OK;
 
-		if ((ast->chip == AST2100) || // GEN2, but not AST1100 (?)
-		    (ast->chip == AST2200) || // GEN3, but not AST2150 (?)
-		    IS_AST_GEN4(ast) || IS_AST_GEN5(ast) ||
-		    IS_AST_GEN6(ast) || IS_AST_GEN7(ast)) {
+		if (ast->support_fullhd) {
 			if ((mode->hdisplay == 1920) && (mode->vdisplay == 1080))
 				return MODE_OK;
 
@@ -1371,12 +1368,7 @@ int ast_mode_config_init(struct ast_device *ast)
 	dev->mode_config.min_height = 0;
 	dev->mode_config.preferred_depth = 24;
 
-	if (ast->chip == AST2100 || // GEN2, but not AST1100 (?)
-	    ast->chip == AST2200 || // GEN3, but not AST2150 (?)
-	    IS_AST_GEN7(ast) ||
-	    IS_AST_GEN6(ast) ||
-	    IS_AST_GEN5(ast) ||
-	    IS_AST_GEN4(ast)) {
+	if (ast->support_fullhd) {
 		dev->mode_config.max_width = 1920;
 		dev->mode_config.max_height = 2048;
 	} else {