[X/B/D][SRU][PATCH 2/2] fonts: Prefer a bigger font for high resolution screens

[Po-Hsu Lin]

From: Takashi Iwai <tiwai at suse.de>

BugLink: https://bugs.launchpad.net/bugs/1851623

Although we may have multiple fonts in kernel, the small 8x16 font is
chosen as default usually unless user specify the boot option.  This
is suboptimal for monitors with high resolutions.

This patch tries to assign a bigger font for such a high resolution by
calculating some penalty value.  This won't change anything for a
standard monitor like Full HD (1920x1080), but for a high res monitor
like UHD 4K, a bigger font like TER16x32 will be chosen once when
enabled in Kconfig.

Signed-off-by: Takashi Iwai <tiwai at suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
(cherry picked from commit dfd19a5004eff03755967086aa04254c3d91b8ec)
Signed-off-by: Po-Hsu Lin <po-hsu.lin at canonical.com>
---
 lib/fonts/fonts.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lib/fonts/fonts.c b/lib/fonts/fonts.c
index 269a829..0edd580 100644
--- a/lib/fonts/fonts.c
+++ b/lib/fonts/fonts.c
@@ -119,7 +119,7 @@ EXPORT_SYMBOL(find_font);
 const struct font_desc *get_default_font(int xres, int yres, u32 font_w,
 					 u32 font_h)
 {
-	int i, c, cc;
+	int i, c, cc, res;
 	const struct font_desc *f, *g;
 
 	g = NULL;
@@ -140,6 +140,11 @@ const struct font_desc *get_default_font(int xres, int yres, u32 font_w,
 		if ((yres < 400) == (f->height <= 8))
 			c += 1000;
 
+		/* prefer a bigger font for high resolution */
+		res = (xres / f->width) * (yres / f->height) / 1000;
+		if (res > 20)
+			c += 20 - res;
+
 		if ((font_w & (1 << (f->width - 1))) &&
 		    (font_h & (1 << (f->height - 1))))
 			c += 1000;
-- 
2.7.4