[PATCH v3 4/4] drm/log: Color the timestamp, to improve readability

[Jocelyn Falempe <jfalempe@xxxxxxxxxx>]

Color the timesamp prefix, similar to dmesg.

Signed-off-by: Jocelyn Falempe <jfalempe@xxxxxxxxxx>
---
 drivers/gpu/drm/drm_log.c | 27 +++++++++++++++++++++------
 1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/drm_log.c b/drivers/gpu/drm/drm_log.c
index 226e206e8b6a..635dff7b37ce 100644
--- a/drivers/gpu/drm/drm_log.c
+++ b/drivers/gpu/drm/drm_log.c
@@ -42,6 +42,7 @@ struct drm_log_scanout {
 	u32 format;
 	u32 px_width;
 	u32 front_color;
+	u32 prefix_color;
 };
 
 struct drm_log {
@@ -97,7 +98,7 @@ static void drm_log_clear_line(struct drm_log_scanout *scanout, u32 line)
 }
 
 static void drm_log_draw_line(struct drm_log_scanout *scanout, const char *s,
-			      unsigned int len)
+			      unsigned int len, unsigned int prefix_len)
 {
 	struct drm_framebuffer *fb = scanout->buffer->fb;
 	struct iosys_map map;
@@ -114,9 +115,10 @@ static void drm_log_draw_line(struct drm_log_scanout *scanout, const char *s,
 
 	iosys_map_incr(&map, r.y1 * fb->pitches[0]);
 	for (i = 0; i < len && i < scanout->columns; i++) {
+		u32 color = (i < prefix_len) ? scanout->prefix_color : scanout->front_color;
 		src = drm_draw_get_char_bitmap(font, s[i], font_pitch);
 		drm_log_blit(&map, fb->pitches[0], src, font_pitch, font->height, font->width,
-			     1, px_width, scanout->front_color);
+			     1, px_width, color);
 		iosys_map_incr(&map, font->width * px_width);
 	}
 
@@ -128,7 +130,7 @@ static void drm_log_draw_line(struct drm_log_scanout *scanout, const char *s,
 }
 
 static void drm_log_draw_new_line(struct drm_log_scanout *scanout,
-				  const char *s, unsigned int len)
+				  const char *s, unsigned int len, unsigned int prefix_len)
 {
 	if (scanout->line == 0) {
 		drm_log_clear_line(scanout, 0);
@@ -137,23 +139,35 @@ static void drm_log_draw_new_line(struct drm_log_scanout *scanout,
 	} else if (scanout->line + 2 < scanout->rows)
 		drm_log_clear_line(scanout, scanout->line + 2);
 
-	drm_log_draw_line(scanout, s, len);
+	drm_log_draw_line(scanout, s, len, prefix_len);
 }
 
+/*
+ * Depends on print_time() in printk.c
+ * Timestamp is written with "[%5lu.%06lu]"
+ */
+#define TS_PREFIX_LEN 13
+
 static void drm_log_draw_kmsg_record(struct drm_log_scanout *scanout,
 				     const char *s, unsigned int len)
 {
+	u32 prefix_len = 0;
+
+	if (len > TS_PREFIX_LEN && s[0] == '[' && s[6] == '.' && s[TS_PREFIX_LEN] == ']')
+		prefix_len = TS_PREFIX_LEN + 1;
+
 	/* do not print the ending \n character */
 	if (s[len - 1] == '\n')
 		len--;
 
 	while (len > scanout->columns) {
-		drm_log_draw_new_line(scanout, s, scanout->columns);
+		drm_log_draw_new_line(scanout, s, scanout->columns, prefix_len);
 		s += scanout->columns;
 		len -= scanout->columns;
+		prefix_len = 0;
 	}
 	if (len)
-		drm_log_draw_new_line(scanout, s, len);
+		drm_log_draw_new_line(scanout, s, len, prefix_len);
 }
 
 static u32 drm_log_find_usable_format(struct drm_plane *plane)
@@ -193,6 +207,7 @@ static int drm_log_setup_modeset(struct drm_client_dev *client,
 	scanout->rows = height / scanout->font->height;
 	scanout->columns = width / scanout->font->width;
 	scanout->front_color = drm_draw_color_from_xrgb8888(0xffffff, format);
+	scanout->prefix_color = drm_draw_color_from_xrgb8888(0x4e9a06, format);
 	return 0;
 }
 
-- 
2.46.0