linux-kernel - [PATCH] fbcon: Increase maximum font width x height to 64 x 64

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Message-ID: <20240313165934.557879-1-samuel.thibault@ens-lyon.org>
Date: Wed, 13 Mar 2024 17:59:34 +0100
From: Samuel Thibault <samuel.thibault@...-lyon.org>
To: linux-kernel@...r.kernel.org,
	Daniel Vetter <daniel@...ll.ch>,
	Helge Deller <deller@....de>,
	Alexey Gladkov <legion@...nel.org>,
	Jiry Slaby <jirislaby@...nel.org>
Cc: Samuel Thibault <samuel.thibault@...-lyon.org>,
	linux-fbdev@...r.kernel.org,
	dri-devel@...ts.freedesktop.org
Subject: [PATCH] fbcon: Increase maximum font width x height to 64 x 64

This remains relatively simple by just enlarging integers.

It wouldn't be that simple to get to the console's 64x128 maximum, as it would
require 128b integers.

Signed-off-by: Samuel Thibault <samuel.thibault@...-lyon.org>
---
 drivers/video/fbdev/core/fbcon.c | 17 ++++++++++-------
 include/linux/fb.h               | 10 +++++-----
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 46823c2e2ba1..849562f92bd5 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -101,6 +101,9 @@ enum {
 	FBCON_LOGO_DONTSHOW	= -3	/* do not show the logo */
 };
 
+#define FBCON_MAX_FONT_WIDTH	(sizeof(((struct fb_pixmap *) 0)->blit_x) * 8)
+#define FBCON_MAX_FONT_HEIGHT	(sizeof(((struct fb_pixmap *) 0)->blit_y) * 8)
+
 static struct fbcon_display fb_display[MAX_NR_CONSOLES];
 
 static struct fb_info *fbcon_registered_fb[FB_MAX];
@@ -2483,12 +2486,12 @@ static int fbcon_set_font(struct vc_data *vc, struct console_font *font,
 	    h > FBCON_SWAP(info->var.rotate, info->var.yres, info->var.xres))
 		return -EINVAL;
 
-	if (font->width > 32 || font->height > 32)
+	if (font->width > FBCON_MAX_FONT_WIDTH || font->height > FBCON_MAX_FONT_HEIGHT)
 		return -EINVAL;
 
 	/* Make sure drawing engine can handle the font */
-	if (!(info->pixmap.blit_x & BIT(font->width - 1)) ||
-	    !(info->pixmap.blit_y & BIT(font->height - 1)))
+	if (!(info->pixmap.blit_x & BIT_ULL(font->width - 1)) ||
+	    !(info->pixmap.blit_y & BIT_ULL(font->height - 1)))
 		return -EINVAL;
 
 	/* Make sure driver can handle the font length */
@@ -3082,8 +3085,8 @@ void fbcon_get_requirement(struct fb_info *info,
 			vc = vc_cons[i].d;
 			if (vc && vc->vc_mode == KD_TEXT &&
 			    info->node == con2fb_map[i]) {
-				caps->x |= 1 << (vc->vc_font.width - 1);
-				caps->y |= 1 << (vc->vc_font.height - 1);
+				caps->x |= 1ULL << (vc->vc_font.width - 1);
+				caps->y |= 1ULL << (vc->vc_font.height - 1);
 				charcnt = vc->vc_font.charcount;
 				if (caps->len < charcnt)
 					caps->len = charcnt;
@@ -3094,8 +3097,8 @@ void fbcon_get_requirement(struct fb_info *info,
 
 		if (vc && vc->vc_mode == KD_TEXT &&
 		    info->node == con2fb_map[fg_console]) {
-			caps->x = 1 << (vc->vc_font.width - 1);
-			caps->y = 1 << (vc->vc_font.height - 1);
+			caps->x = 1ULL << (vc->vc_font.width - 1);
+			caps->y = 1ULL << (vc->vc_font.height - 1);
 			caps->len = vc->vc_font.charcount;
 		}
 	}
diff --git a/include/linux/fb.h b/include/linux/fb.h
index 05dc9624897d..2bac166cd3f2 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -144,8 +144,8 @@ struct fb_event {
 };
 
 struct fb_blit_caps {
-	u32 x;
-	u32 y;
+	u64 x;
+	u64 y;
 	u32 len;
 	u32 flags;
 };
@@ -192,10 +192,10 @@ struct fb_pixmap {
 	u32 scan_align;		/* alignment per scanline		*/
 	u32 access_align;	/* alignment per read/write (bits)	*/
 	u32 flags;		/* see FB_PIXMAP_*			*/
-	u32 blit_x;             /* supported bit block dimensions (1-32)*/
-	u32 blit_y;             /* Format: blit_x = 1 << (width - 1)    */
+	u64 blit_x;             /* supported bit block dimensions (1-64)*/
+	u64 blit_y;             /* Format: blit_x = 1 << (width - 1)    */
 	                        /*         blit_y = 1 << (height - 1)   */
-	                        /* if 0, will be set to 0xffffffff (all)*/
+	                        /* if 0, will be set to ~0ull (all)     */
 	/* access methods */
 	void (*writeio)(struct fb_info *info, void __iomem *dst, void *src, unsigned int size);
 	void (*readio) (struct fb_info *info, void *dst, void __iomem *src, unsigned int size);
-- 
2.39.2