Add a kmsg option, which will display the last lines of kmsg,
and should be similar to fbcon.
Add a drm.panic_screen module parameter, so you can choose between
the different panic screens available.
two options currently, but more will be added later:
* "user": a short message telling the user to reboot the machine.
* "kmsg": fill the screen with the last lines of kmsg.
You can even change it at runtime by writing to
/sys/module/drm/parameters/panic_screen
v2:
* use module parameter instead of Kconfig choice
(Javier Martinez Canillas)
Signed-off-by: Jocelyn Falempe <jfalempe@xxxxxxxxxx>
---
drivers/gpu/drm/Kconfig | 11 ++++
drivers/gpu/drm/drm_panic.c | 108 ++++++++++++++++++++++++++++++++----
2 files changed, 109 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 9703429de6b9..944815cee080 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -137,6 +137,17 @@ config DRM_PANIC_DEBUG
This is unsafe and should not be enabled on a production build.
If in doubt, say "N".
+config DRM_PANIC_SCREEN
+ string "Panic screen formater"
+ default "user"
+ depends on DRM_PANIC
+ help
+ This option enable to choose what will be displayed when a kernel
+ panic occurs. You can choose between "user", a short message telling
+ the user to reboot the system, or "kmsg" which will display the last
+ lines of kmsg.
+ Default is "user"
+
config DRM_DEBUG_DP_MST_TOPOLOGY_REFS
bool "Enable refcount backtrace history in the DP MST helpers"
depends on STACKTRACE_SUPPORT
diff --git a/drivers/gpu/drm/drm_panic.c b/drivers/gpu/drm/drm_panic.c
index 5dc9e98108ed..2e11273a8ad6 100644
--- a/drivers/gpu/drm/drm_panic.c
+++ b/drivers/gpu/drm/drm_panic.c
@@ -12,6 +12,7 @@
#include <linux/kmsg_dump.h>
#include <linux/list.h>
#include <linux/module.h>
+#include <linux/printk.h>
#include <linux/types.h>
#include <drm/drm_drv.h>
@@ -27,6 +28,12 @@ MODULE_AUTHOR("Jocelyn Falempe");
MODULE_DESCRIPTION("DRM panic handler");
MODULE_LICENSE("GPL");
+static char drm_panic_screen[16] = CONFIG_DRM_PANIC_SCREEN;
+module_param_string(panic_screen, drm_panic_screen, sizeof(drm_panic_screen), 0644);
+MODULE_PARM_DESC(panic_screen,
+ "Choose what will be displayed by drm_panic, 'user' or 'kmsg' [default="
+ CONFIG_DRM_PANIC_SCREEN "]");
+
/**
* DOC: overview
*
@@ -437,24 +444,18 @@ static void draw_txt_rectangle(struct drm_scanout_buffer *sb,
}
}
-/*
- * Draw the panic message at the center of the screen
- */
-static void draw_panic_static(struct drm_scanout_buffer *sb)
+static void draw_panic_static_user(struct drm_scanout_buffer *sb)
{
size_t msg_lines = ARRAY_SIZE(panic_msg);
size_t logo_lines = ARRAY_SIZE(logo);
- u32 fg_color = CONFIG_DRM_PANIC_FOREGROUND_COLOR;
- u32 bg_color = CONFIG_DRM_PANIC_BACKGROUND_COLOR;
+ u32 fg_color = convert_from_xrgb8888(CONFIG_DRM_PANIC_FOREGROUND_COLOR, sb->format->format);
+ u32 bg_color = convert_from_xrgb8888(CONFIG_DRM_PANIC_BACKGROUND_COLOR, sb->format->format);
const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL);
struct drm_rect r_screen, r_logo, r_msg;
if (!font)
return;
- fg_color = convert_from_xrgb8888(fg_color, sb->format->format);
- bg_color = convert_from_xrgb8888(bg_color, sb->format->format);
-
r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);
r_logo = DRM_RECT_INIT(0, 0,
@@ -477,6 +478,84 @@ static void draw_panic_static(struct drm_scanout_buffer *sb)
draw_txt_rectangle(sb, font, panic_msg, msg_lines, true, &r_msg, fg_color);
}
+
+/*
+ * Draw one line of kmsg, and handle wrapping if it won't fit in the screen width.
+ * Return the y-offset of the next line.
+ */
+static int draw_line_with_wrap(struct drm_scanout_buffer *sb, const struct font_desc *font,
+ struct drm_panic_line *line, int yoffset, u32 fg_color)
+{
+ int chars_per_row = sb->width / font->width;
+ struct drm_rect r_txt = DRM_RECT_INIT(0, yoffset, sb->width, sb->height);
+ struct drm_panic_line line_wrap;
+
+ if (line->len > chars_per_row) {
+ line_wrap.len = line->len % chars_per_row;
+ line_wrap.txt = line->txt + line->len - line_wrap.len;
+ draw_txt_rectangle(sb, font, &line_wrap, 1, false, &r_txt, fg_color);
+ r_txt.y1 -= font->height;
+ if (r_txt.y1 < 0)
+ return r_txt.y1;
+ while (line_wrap.txt > line->txt) {
+ line_wrap.txt -= chars_per_row;
+ line_wrap.len = chars_per_row;
+ draw_txt_rectangle(sb, font, &line_wrap, 1, false, &r_txt, fg_color);
+ r_txt.y1 -= font->height;
+ if (r_txt.y1 < 0)
+ return r_txt.y1;
+ }
+ } else {
+ draw_txt_rectangle(sb, font, line, 1, false, &r_txt, fg_color);
+ r_txt.y1 -= font->height;
+ }
+ return r_txt.y1;
+}
+
+/*
+ * Draw the kmsg buffer to the screen, starting from the youngest message at the bottom,
+ * and going up until reaching the top of the screen.
+ */
+static void draw_panic_static_kmsg(struct drm_scanout_buffer *sb)
+{
+ u32 fg_color = convert_from_xrgb8888(CONFIG_DRM_PANIC_FOREGROUND_COLOR, sb->format->format);
+ u32 bg_color = convert_from_xrgb8888(CONFIG_DRM_PANIC_BACKGROUND_COLOR, sb->format->format);
+ const struct font_desc *font = get_default_font(sb->width, sb->height, NULL, NULL);
+ struct drm_rect r_screen = DRM_RECT_INIT(0, 0, sb->width, sb->height);
+ struct kmsg_dump_iter iter;
+ char kmsg_buf[512];
+ size_t kmsg_len;
+ struct drm_panic_line line;
+ int yoffset = sb->height - font->height - (sb->height % font->height) / 2;
+
+ if (!font)
+ return;
+
+ /* Fill with the background color, and draw text on top */
+ drm_panic_fill(sb, &r_screen, bg_color);
+
+ kmsg_dump_rewind(&iter);
+ while (kmsg_dump_get_buffer(&iter, false, kmsg_buf, sizeof(kmsg_buf), &kmsg_len)) {
+ char *start;
+ char *end;
+
+ /* ignore terminating NUL and newline */
+ start = kmsg_buf + kmsg_len - 2;
+ end = kmsg_buf + kmsg_len - 1;
+ while (start > kmsg_buf && yoffset >= 0) {
+ while (start > kmsg_buf && *start != '\n')
+ start--;
+ /* don't count the newline character */
+ line.txt = start + (start == kmsg_buf ? 0 : 1);
+ line.len = end - line.txt;
+
+ yoffset = draw_line_with_wrap(sb, font, &line, yoffset, fg_color);
+ end = start;
+ start--;
+ }
+ }
+}
+
/*
* drm_panic_is_format_supported()
* @format: a fourcc color code
@@ -491,6 +570,15 @@ static bool drm_panic_is_format_supported(const struct drm_format_info *format)
return convert_from_xrgb8888(0xffffff, format->format) != 0;
}
+static void draw_panic_dispatch(struct drm_scanout_buffer *sb)
+{
+ if (!strcmp(drm_panic_screen, "kmsg")) {
+ draw_panic_static_kmsg(sb);
+ } else {
+ draw_panic_static_user(sb);
+ }
+}
+
static void draw_panic_plane(struct drm_plane *plane)
{
struct drm_scanout_buffer sb;
@@ -503,7 +591,7 @@ static void draw_panic_plane(struct drm_plane *plane)
ret = plane->helper_private->get_scanout_buffer(plane, &sb);
if (!ret && drm_panic_is_format_supported(sb.format)) {
- draw_panic_static(&sb);
+ draw_panic_dispatch(&sb);
if (plane->helper_private->panic_flush)
plane->helper_private->panic_flush(plane);
}
--
2.45.1
