[kbd] [PATCHv3 0/3] VT: Support >32x32 fonts for hidpi displays

[kbd] [PATCHv3 0/3] VT: Support >32x32 fonts for hidpi displays

[Samuel Thibault]

Hello,

This patch series adds to Linux and kbd the support for fonts larger than 32x32
by dropping the oldish VGA constraints that don't apply to fb-based consoles.

The change from v2 is only to completely drop the sisusb part, so that it
applies cleanly e.g. on latest Linus' tree.

Samuel

[kbd] [PATCHv3 1/3] VT: Add height parameter to con_font_get/set consw operations

[Samuel Thibault]

The current con_font_get/set API currently hardcodes a 32-pixel-tall
limitation, which only dates from the old VGA hardware which could not
handle taller fonts than that.

This change just adds a vpitch parameter to release this
constraint. Drivers which do not support vpitch != 32 can just return
EINVAL when it is not 32, font loading tools will revert to trying 32
and succeed.

This change makes the fbcon driver consider vpitch appropriately, thus
making it able to load large fonts.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

---
V1 -> V3: Drop (bogus) sisusb_con.c change, it was phased out

Index: linux-6.0/drivers/tty/vt/vt.c
===================================================================
--- linux-6.0.orig/drivers/tty/vt/vt.c
+++ linux-6.0/drivers/tty/vt/vt.c
@@ -4604,7 +4604,7 @@ static int con_font_get(struct vc_data *
 	if (vc->vc_mode != KD_TEXT)
 		rc = -EINVAL;
 	else if (vc->vc_sw->con_font_get)
-		rc = vc->vc_sw->con_font_get(vc, &font);
+		rc = vc->vc_sw->con_font_get(vc, &font, 32);
 	else
 		rc = -ENOSYS;
 	console_unlock();
@@ -4665,7 +4665,7 @@ static int con_font_set(struct vc_data *
 	else if (vc->vc_sw->con_font_set) {
 		if (vc_is_sel(vc))
 			clear_selection();
-		rc = vc->vc_sw->con_font_set(vc, &font, op->flags);
+		rc = vc->vc_sw->con_font_set(vc, &font, 32, op->flags);
 	} else
 		rc = -ENOSYS;
 	console_unlock();
Index: linux-6.0/drivers/video/console/vgacon.c
===================================================================
--- linux-6.0.orig/drivers/video/console/vgacon.c
+++ linux-6.0/drivers/video/console/vgacon.c
@@ -1029,7 +1029,7 @@ static int vgacon_adjust_height(struct v
 }
 
 static int vgacon_font_set(struct vc_data *c, struct console_font *font,
-			   unsigned int flags)
+			   unsigned int vpitch, unsigned int flags)
 {
 	unsigned charcount = font->charcount;
 	int rc;
@@ -1037,7 +1037,7 @@ static int vgacon_font_set(struct vc_dat
 	if (vga_video_type < VIDEO_TYPE_EGAM)
 		return -EINVAL;
 
-	if (font->width != VGA_FONTWIDTH ||
+	if (font->width != VGA_FONTWIDTH || vpitch != 32 ||
 	    (charcount != 256 && charcount != 512))
 		return -EINVAL;
 
@@ -1050,9 +1050,9 @@ static int vgacon_font_set(struct vc_dat
 	return rc;
 }
 
-static int vgacon_font_get(struct vc_data *c, struct console_font *font)
+static int vgacon_font_get(struct vc_data *c, struct console_font *font, unsigned int vpitch)
 {
-	if (vga_video_type < VIDEO_TYPE_EGAM)
+	if (vga_video_type < VIDEO_TYPE_EGAM || vpitch != 32)
 		return -EINVAL;
 
 	font->width = VGA_FONTWIDTH;
Index: linux-6.0/drivers/video/fbdev/core/fbcon.c
===================================================================
--- linux-6.0.orig/drivers/video/fbdev/core/fbcon.c
+++ linux-6.0/drivers/video/fbdev/core/fbcon.c
@@ -2271,7 +2271,7 @@ static int fbcon_debug_leave(struct vc_d
 	return 0;
 }
 
-static int fbcon_get_font(struct vc_data *vc, struct console_font *font)
+static int fbcon_get_font(struct vc_data *vc, struct console_font *font, unsigned int vpitch)
 {
 	u8 *fontdata = vc->vc_font.data;
 	u8 *data = font->data;
@@ -2290,8 +2290,8 @@ static int fbcon_get_font(struct vc_data
 
 		for (i = 0; i < font->charcount; i++) {
 			memcpy(data, fontdata, j);
-			memset(data + j, 0, 32 - j);
-			data += 32;
+			memset(data + j, 0, vpitch - j);
+			data += vpitch;
 			fontdata += j;
 		}
 	} else if (font->width <= 16) {
@@ -2301,8 +2301,8 @@ static int fbcon_get_font(struct vc_data
 
 		for (i = 0; i < font->charcount; i++) {
 			memcpy(data, fontdata, j);
-			memset(data + j, 0, 64 - j);
-			data += 64;
+			memset(data + j, 0, 2*vpitch - j);
+			data += 2*vpitch;
 			fontdata += j;
 		}
 	} else if (font->width <= 24) {
@@ -2316,8 +2316,8 @@ static int fbcon_get_font(struct vc_data
 				*data++ = fontdata[2];
 				fontdata += sizeof(u32);
 			}
-			memset(data, 0, 3 * (32 - j));
-			data += 3 * (32 - j);
+			memset(data, 0, 3 * (vpitch - j));
+			data += 3 * (vpitch - j);
 		}
 	} else {
 		j = vc->vc_font.height * 4;
@@ -2326,8 +2326,8 @@ static int fbcon_get_font(struct vc_data
 
 		for (i = 0; i < font->charcount; i++) {
 			memcpy(data, fontdata, j);
-			memset(data + j, 0, 128 - j);
-			data += 128;
+			memset(data + j, 0, 4 * vpitch - j);
+			data += 4 * vpitch;
 			fontdata += j;
 		}
 	}
@@ -2461,19 +2461,12 @@ err_out:
 }
 
 /*
- *  User asked to set font; we are guaranteed that
- *	a) width and height are in range 1..32
- *	b) charcount does not exceed 512
- *  but lets not assume that, since someone might someday want to use larger
- *  fonts. And charcount of 512 is small for unicode support.
- *
- *  However, user space gives the font in 32 rows , regardless of
- *  actual font height. So a new API is needed if support for larger fonts
- *  is ever implemented.
+ *  User asked to set font; we are guaranteed that charcount does not exceed 512
+ *  but lets not assume that, since charcount of 512 is small for unicode support.
  */
 
 static int fbcon_set_font(struct vc_data *vc, struct console_font *font,
-			  unsigned int flags)
+			  unsigned int vpitch, unsigned int flags)
 {
 	struct fb_info *info = fbcon_info_from_console(vc->vc_num);
 	unsigned charcount = font->charcount;
@@ -2516,7 +2509,7 @@ static int fbcon_set_font(struct vc_data
 	FNTSIZE(new_data) = size;
 	REFCOUNT(new_data) = 0;	/* usage counter */
 	for (i=0; i< charcount; i++) {
-		memcpy(new_data + i*h*pitch, data +  i*32*pitch, h*pitch);
+		memcpy(new_data + i*h*pitch, data +  i*vpitch*pitch, h*pitch);
 	}
 
 	/* Since linux has a nice crc32 function use it for counting font
Index: linux-6.0/include/linux/console.h
===================================================================
--- linux-6.0.orig/include/linux/console.h
+++ linux-6.0/include/linux/console.h
@@ -58,8 +58,9 @@ struct consw {
 	int	(*con_switch)(struct vc_data *vc);
 	int	(*con_blank)(struct vc_data *vc, int blank, int mode_switch);
 	int	(*con_font_set)(struct vc_data *vc, struct console_font *font,
-			unsigned int flags);
-	int	(*con_font_get)(struct vc_data *vc, struct console_font *font);
+			unsigned int vpitch, unsigned int flags);
+	int	(*con_font_get)(struct vc_data *vc, struct console_font *font,
+			unsigned int vpitch);
 	int	(*con_font_default)(struct vc_data *vc,
 			struct console_font *font, char *name);
 	int     (*con_resize)(struct vc_data *vc, unsigned int width,
Index: linux-6.0/drivers/video/console/newport_con.c
===================================================================
--- linux-6.0.orig/drivers/video/console/newport_con.c
+++ linux-6.0/drivers/video/console/newport_con.c
@@ -497,7 +497,7 @@ static int newport_blank(struct vc_data
 	return 1;
 }
 
-static int newport_set_font(int unit, struct console_font *op)
+static int newport_set_font(int unit, struct console_font *op, unsigned int vpitch)
 {
 	int w = op->width;
 	int h = op->height;
@@ -507,7 +507,7 @@ static int newport_set_font(int unit, st
 
 	/* ladis: when I grow up, there will be a day... and more sizes will
 	 * be supported ;-) */
-	if ((w != 8) || (h != 16)
+	if ((w != 8) || (h != 16) || (vpitch != 32)
 	    || (op->charcount != 256 && op->charcount != 512))
 		return -EINVAL;
 
@@ -569,9 +569,10 @@ static int newport_font_default(struct v
 	return newport_set_def_font(vc->vc_num, op);
 }
 
-static int newport_font_set(struct vc_data *vc, struct console_font *font, unsigned flags)
+static int newport_font_set(struct vc_data *vc, struct console_font *font,
+			    unsigned int vpitch, unsigned int flags)
 {
-	return newport_set_font(vc->vc_num, font);
+	return newport_set_font(vc->vc_num, font, vpitch);
 }
 
 static bool newport_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
Index: linux-6.0/drivers/video/console/sticon.c
===================================================================
--- linux-6.0.orig/drivers/video/console/sticon.c
+++ linux-6.0/drivers/video/console/sticon.c
@@ -169,7 +169,8 @@ static int sticon_set_def_font(int unit,
 	return 0;
 }
 
-static int sticon_set_font(struct vc_data *vc, struct console_font *op)
+static int sticon_set_font(struct vc_data *vc, struct console_font *op,
+			   unsigned int vpitch)
 {
 	struct sti_struct *sti = sticon_sti;
 	int vc_cols, vc_rows, vc_old_cols, vc_old_rows;
@@ -181,7 +182,7 @@ static int sticon_set_font(struct vc_dat
 	struct sti_cooked_font *cooked_font;
 	unsigned char *data = op->data, *p;
 
-	if ((w < 6) || (h < 6) || (w > 32) || (h > 32)
+	if ((w < 6) || (h < 6) || (w > 32) || (h > 32) || (vpitch != 32)
 	    || (op->charcount != 256 && op->charcount != 512))
 		return -EINVAL;
 	pitch = ALIGN(w, 8) / 8;
@@ -267,9 +268,9 @@ static int sticon_font_default(struct vc
 }
 
 static int sticon_font_set(struct vc_data *vc, struct console_font *font,
-			   unsigned int flags)
+			   unsigned int vpitch, unsigned int flags)
 {
-	return sticon_set_font(vc, font);
+	return sticon_set_font(vc, font, vpitch);
 }
 
 static void sticon_init(struct vc_data *c, int init)

[kbd] [PATCHv3 2/3] VT: Add KD_FONT_OP_SET/GET_TALL operations

[Samuel Thibault]

The KD_FONT_OP_SET/GET operations hardcode vpitch to be 32 pixels,
which only dates from the old VGA hardware which as asserting this.

Drivers such as fbcon however do not have such limitation, so this
introduces KD_FONT_OP_SET/GET_TALL operations, which userland can try
to use to avoid this limitation, thus opening the patch to >32 pixels
font height.

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

Index: linux-6.0/drivers/tty/vt/vt.c
===================================================================
--- linux-6.0.orig/drivers/tty/vt/vt.c
+++ linux-6.0/drivers/tty/vt/vt.c
@@ -4592,6 +4592,7 @@ static int con_font_get(struct vc_data *
 	struct console_font font;
 	int rc = -EINVAL;
 	int c;
+	unsigned int vpitch = op->op == KD_FONT_OP_GET_TALL ? op->height : 32;
 
 	if (op->data) {
 		font.data = kmalloc(max_font_size, GFP_KERNEL);
@@ -4604,7 +4605,7 @@ static int con_font_get(struct vc_data *
 	if (vc->vc_mode != KD_TEXT)
 		rc = -EINVAL;
 	else if (vc->vc_sw->con_font_get)
-		rc = vc->vc_sw->con_font_get(vc, &font, 32);
+		rc = vc->vc_sw->con_font_get(vc, &font, vpitch);
 	else
 		rc = -ENOSYS;
 	console_unlock();
@@ -4612,7 +4613,7 @@ static int con_font_get(struct vc_data *
 	if (rc)
 		goto out;
 
-	c = (font.width+7)/8 * 32 * font.charcount;
+	c = (font.width+7)/8 * vpitch * font.charcount;
 
 	if (op->data && font.charcount > op->charcount)
 		rc = -ENOSPC;
@@ -4638,6 +4639,7 @@ static int con_font_set(struct vc_data *
 	struct console_font font;
 	int rc = -EINVAL;
 	int size;
+	unsigned int vpitch = op->op == KD_FONT_OP_SET_TALL ? op->height : 32;
 
 	if (vc->vc_mode != KD_TEXT)
 		return -EINVAL;
@@ -4647,7 +4649,9 @@ static int con_font_set(struct vc_data *
 		return -EINVAL;
 	if (op->width <= 0 || op->width > 32 || !op->height || op->height > 32)
 		return -EINVAL;
-	size = (op->width+7)/8 * 32 * op->charcount;
+	if (vpitch < op->height)
+		return -EINVAL;
+	size = (op->width+7)/8 * vpitch * op->charcount;
 	if (size > max_font_size)
 		return -ENOSPC;
 
@@ -4665,7 +4669,7 @@ static int con_font_set(struct vc_data *
 	else if (vc->vc_sw->con_font_set) {
 		if (vc_is_sel(vc))
 			clear_selection();
-		rc = vc->vc_sw->con_font_set(vc, &font, 32, op->flags);
+		rc = vc->vc_sw->con_font_set(vc, &font, vpitch, op->flags);
 	} else
 		rc = -ENOSYS;
 	console_unlock();
@@ -4711,8 +4715,10 @@ int con_font_op(struct vc_data *vc, stru
 {
 	switch (op->op) {
 	case KD_FONT_OP_SET:
+	case KD_FONT_OP_SET_TALL:
 		return con_font_set(vc, op);
 	case KD_FONT_OP_GET:
+	case KD_FONT_OP_GET_TALL:
 		return con_font_get(vc, op);
 	case KD_FONT_OP_SET_DEFAULT:
 		return con_font_default(vc, op);
Index: linux-6.0/include/uapi/linux/kd.h
===================================================================
--- linux-6.0.orig/include/uapi/linux/kd.h
+++ linux-6.0/include/uapi/linux/kd.h
@@ -161,19 +161,25 @@ struct console_font_op {
 	unsigned int flags;	/* KD_FONT_FLAG_* */
 	unsigned int width, height;	/* font size */
 	unsigned int charcount;
-	unsigned char __user *data;	/* font data with height fixed to 32 */
+	unsigned char __user *data;	/* font data with vpitch fixed to 32 for
+					 * KD_FONT_OP_SET/GET
+					 */
 };
 
 struct console_font {
 	unsigned int width, height;	/* font size */
 	unsigned int charcount;
-	unsigned char *data;	/* font data with height fixed to 32 */
+	unsigned char *data;	/* font data with vpitch fixed to 32 for
+				 * KD_FONT_OP_SET/GET
+				 */
 };
 
 #define KD_FONT_OP_SET		0	/* Set font */
 #define KD_FONT_OP_GET		1	/* Get font */
 #define KD_FONT_OP_SET_DEFAULT	2	/* Set font to default, data points to name / NULL */
 #define KD_FONT_OP_COPY		3	/* Obsolete, do not use */
+#define KD_FONT_OP_SET_TALL	4	/* Set font with vpitch = height */
+#define KD_FONT_OP_GET_TALL	5	/* Get font with vpitch = height */
 
 #define KD_FONT_FLAG_DONT_RECALC 	1	/* Don't recalculate hw charcell size [compat] */
 

[kbd] [PATCHv3 3/3] VT: Bump font size limitation to 64x128 pixels

[Samuel Thibault]

This moves 32x32 font size limitation checking down to drivers, so that
fbcon can allow large fonts.

We still keep a limitation to 64x128 pixels so as to have a simple bounded
allocation for con_font_get and in the userland kbd tool. That glyph size
will however be enough to have 128x36 characters on a "16/9 8K display".

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

---
V1 -> V2: Switch con_font_get to kvmalloc/kvfree instead of kmalloc/kfree
V1 -> V3: Drop sisusb_con.c change, it was phased out

Index: linux-6.0/drivers/tty/vt/vt.c
===================================================================
--- linux-6.0.orig/drivers/tty/vt/vt.c
+++ linux-6.0/drivers/tty/vt/vt.c
@@ -4575,17 +4575,20 @@ void reset_palette(struct vc_data *vc)
 /*
  *  Font switching
  *
- *  Currently we only support fonts up to 32 pixels wide, at a maximum height
- *  of 32 pixels. Userspace fontdata is stored with 32 bytes (shorts/ints, 
- *  depending on width) reserved for each character which is kinda wasty, but 
- *  this is done in order to maintain compatibility with the EGA/VGA fonts. It 
- *  is up to the actual low-level console-driver convert data into its favorite
- *  format (maybe we should add a `fontoffset' field to the `display'
- *  structure so we won't have to convert the fontdata all the time.
+ *  Currently we only support fonts up to 128 pixels wide, at a maximum height
+ *  of 128 pixels. Userspace fontdata may have to be stored with 32 bytes
+ *  (shorts/ints, depending on width) reserved for each character which is
+ *  kinda wasty, but this is done in order to maintain compatibility with the
+ *  EGA/VGA fonts. It is up to the actual low-level console-driver convert data
+ *  into its favorite format (maybe we should add a `fontoffset' field to the
+ *  `display' structure so we won't have to convert the fontdata all the time.
  *  /Jes
  */
 
-#define max_font_size 65536
+#define max_font_width	64
+#define max_font_height	128
+#define max_font_glyphs	512
+#define max_font_size	(max_font_glyphs*max_font_width*max_font_height)
 
 static int con_font_get(struct vc_data *vc, struct console_font_op *op)
 {
@@ -4595,7 +4598,7 @@ static int con_font_get(struct vc_data *
 	unsigned int vpitch = op->op == KD_FONT_OP_GET_TALL ? op->height : 32;
 
 	if (op->data) {
-		font.data = kmalloc(max_font_size, GFP_KERNEL);
+		font.data = kvmalloc(max_font_size, GFP_KERNEL);
 		if (!font.data)
 			return -ENOMEM;
 	} else
@@ -4630,7 +4633,7 @@ static int con_font_get(struct vc_data *
 		rc = -EFAULT;
 
 out:
-	kfree(font.data);
+	kvfree(font.data);
 	return rc;
 }
 
@@ -4645,9 +4648,10 @@ static int con_font_set(struct vc_data *
 		return -EINVAL;
 	if (!op->data)
 		return -EINVAL;
-	if (op->charcount > 512)
+	if (op->charcount > max_font_glyphs)
 		return -EINVAL;
-	if (op->width <= 0 || op->width > 32 || !op->height || op->height > 32)
+	if (op->width <= 0 || op->width > max_font_width || !op->height ||
+	    op->height > max_font_height)
 		return -EINVAL;
 	if (vpitch < op->height)
 		return -EINVAL;
Index: linux-6.0/drivers/video/console/vgacon.c
===================================================================
--- linux-6.0.orig/drivers/video/console/vgacon.c
+++ linux-6.0/drivers/video/console/vgacon.c
@@ -1037,7 +1037,7 @@ static int vgacon_font_set(struct vc_dat
 	if (vga_video_type < VIDEO_TYPE_EGAM)
 		return -EINVAL;
 
-	if (font->width != VGA_FONTWIDTH || vpitch != 32 ||
+	if (font->width != VGA_FONTWIDTH || font->height > 32 || vpitch != 32 ||
 	    (charcount != 256 && charcount != 512))
 		return -EINVAL;
 
Index: linux-6.0/drivers/video/fbdev/core/fbcon.c
===================================================================
--- linux-6.0.orig/drivers/video/fbdev/core/fbcon.c
+++ linux-6.0/drivers/video/fbdev/core/fbcon.c
@@ -2279,6 +2279,8 @@ static int fbcon_get_font(struct vc_data
 
 	font->width = vc->vc_font.width;
 	font->height = vc->vc_font.height;
+	if (font->height > vpitch)
+		return -ENOSPC;
 	font->charcount = vc->vc_hi_font_mask ? 512 : 256;
 	if (!font->data)
 		return 0;

Re: [kbd] [PATCHv3 0/3] VT: Support >32x32 fonts for hidpi displays

[Greg Kroah-Hartman]

On Thu, Jan 19, 2023 at 04:19:14PM +0100, Samuel Thibault wrote:
> Hello,
> 
> This patch series adds to Linux and kbd the support for fonts larger than 32x32
> by dropping the oldish VGA constraints that don't apply to fb-based consoles.
> 
> The change from v2 is only to completely drop the sisusb part, so that it
> applies cleanly e.g. on latest Linus' tree.

That was fast, thanks!!!  I'll go queue this up now.