[PATCH i-g-t 2/4] tools/displaytop: Add Display debugfs entry for display top
Adith Narein T
adith.narein.t at intel.com
Thu May 29 14:23:41 UTC 2025
This patch adds support for reading, displaying & dumping of display-related
debugfs entries within the DisplayTop tool. Users can now browse and dump
relevant i915 debugfs entries related to the display pipeline, enabling
easier real-time inspection and analysis of driver-level state.
Signed-off-by: Adith Narein T <adith.narein.t at intel.com>
---
tools/displaytop/README.md | 1 +
tools/displaytop/include/data.h | 2 +
tools/displaytop/include/display.h | 2 +
tools/displaytop/include/populate.h | 1 +
tools/displaytop/include/utils.h | 2 +
tools/displaytop/meson.build | 2 +
tools/displaytop/src/display_debugfs.c | 133 ++++++++++++++++++
tools/displaytop/src/populate.c | 1 +
.../displaytop/src/populate_display_debugfs.c | 99 +++++++++++++
tools/displaytop/src/utils_driver.c | 54 +++++++
10 files changed, 297 insertions(+)
create mode 100644 tools/displaytop/src/display_debugfs.c
create mode 100644 tools/displaytop/src/populate_display_debugfs.c
diff --git a/tools/displaytop/README.md b/tools/displaytop/README.md
index 7349f0760..3e123ee04 100644
--- a/tools/displaytop/README.md
+++ b/tools/displaytop/README.md
@@ -7,6 +7,7 @@ A terminal-based tool for monitoring and debugging the display pipeline.
- Terminal UI using `ncurses`
- Dump feature for all the menus
- Real-time display Configuration
+- view Live Display Debugfs in a terminal ui
---
diff --git a/tools/displaytop/include/data.h b/tools/displaytop/include/data.h
index 0bc1b51d4..a6a6275f7 100644
--- a/tools/displaytop/include/data.h
+++ b/tools/displaytop/include/data.h
@@ -34,4 +34,6 @@ extern Node *root; /* shared throughout the program */
#define DRM_PRIMARY_PREFIX "card"
#define DRM_RENDER_PREFIX "renderD"
+#define DEBUGFS_DRI_PATH "/sys/kernel/debug/dri"
+
#endif
\ No newline at end of file
diff --git a/tools/displaytop/include/display.h b/tools/displaytop/include/display.h
index db77ef785..dc9e9b4d2 100644
--- a/tools/displaytop/include/display.h
+++ b/tools/displaytop/include/display.h
@@ -43,4 +43,6 @@ void display_framebuffer(WINDOW *pad, Node *node, int *content_line);
void display_summary(WINDOW *pad, Node *node, int *content_line);
+void display_debugfs_file(WINDOW *pad, Node *node, int *content_line);
+
#endif
\ No newline at end of file
diff --git a/tools/displaytop/include/populate.h b/tools/displaytop/include/populate.h
index 5a5241355..fee62bbb1 100644
--- a/tools/displaytop/include/populate.h
+++ b/tools/displaytop/include/populate.h
@@ -33,5 +33,6 @@
void populate_data(void);
void initialize_display_config(void);
+void initialize_display_debugfs(void);
#endif
\ No newline at end of file
diff --git a/tools/displaytop/include/utils.h b/tools/displaytop/include/utils.h
index eef5df5f3..17af75b8c 100644
--- a/tools/displaytop/include/utils.h
+++ b/tools/displaytop/include/utils.h
@@ -112,4 +112,6 @@ const char *get_basic_modifier_str(uint64_t modifier);
const char *get_connector_type_name(uint32_t connector_type);
const char *get_encoder_type_name(uint32_t encoder_type);
+char *find_debugfs_dir(void);
+
#endif
\ No newline at end of file
diff --git a/tools/displaytop/meson.build b/tools/displaytop/meson.build
index 2d8c9d418..1f51a3cf2 100644
--- a/tools/displaytop/meson.build
+++ b/tools/displaytop/meson.build
@@ -58,6 +58,8 @@ if have_displaytop
'src/utils_driver.c',
'src/utils_drm.c',
'src/utils_search.c',
+ 'src/populate_display_debugfs.c',
+ 'src/display_debugfs.c',
)
if meson.is_subproject()
diff --git a/tools/displaytop/src/display_debugfs.c b/tools/displaytop/src/display_debugfs.c
new file mode 100644
index 000000000..9b7467e8a
--- /dev/null
+++ b/tools/displaytop/src/display_debugfs.c
@@ -0,0 +1,133 @@
+/*
+ * Copyright © 2025 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include "display.h"
+#include "utils.h"
+
+/**
+ * /docs
+ * build_full_path - Constructs the full filesystem path for a given node in the debugfs tree.
+ * @node: Pointer to the Node structure for which the path is to be built.
+ * @full_path: Buffer to store the resulting full path as a null-terminated string.
+ * @size: Size of the @full_path buffer.
+ *
+ * This function traverses the parent hierarchy of the given node, collecting
+ * each node's name (excluding a trailing '*' if present), and constructs the
+ * relative path from the root node named "Display Debugfs" down to the given node.
+ * The resulting path is prefixed with the debugfs directory path (as returned by
+ * find_debugfs_dir()) and stored in @full_path.
+ *
+ * The function ensures that the constructed path does not exceed the provided buffer size.
+ */
+static void build_full_path(Node *node, char *full_path, size_t size)
+{
+ int i;
+ int depth = 0;
+ char segments[20][256];
+ char relative_path[1024] = {0};
+
+ node = node;
+ while (node && node->parent && strcmp(node->name, "Display Debugfs") != 0)
+ {
+ char *name = node->name;
+ size_t name_len = strlen(name);
+
+ if (name_len > 0 && name[name_len - 1] == '*')
+ {
+ snprintf(segments[depth], sizeof(segments[depth]), "%.*s", (int)(name_len - 1), name);
+ }
+ else
+ {
+ snprintf(segments[depth], sizeof(segments[depth]), "%s", name);
+ }
+
+ depth++;
+ node = node->parent;
+ }
+
+ for (i = depth - 1; i >= 0; i--)
+ {
+ strncat(relative_path, "/", sizeof(relative_path) - strlen(relative_path) - 1);
+ strncat(relative_path, segments[i], sizeof(relative_path) - strlen(relative_path) - 1);
+ }
+
+ snprintf(full_path, size, "%s%s", find_debugfs_dir(), relative_path);
+}
+
+void display_debugfs_file(WINDOW *pad, Node *node, int *content_line)
+{
+ int line = 0;
+ int max_x = getmaxx(pad) - 4;
+ int start, break_point;
+
+ FILE *file;
+ char temp[1024];
+ char buffer[1024];
+ char full_file_path[1024] = {0};
+
+ build_full_path(node, full_file_path, sizeof(full_file_path));
+
+ file = fopen(full_file_path, "r");
+ if (!file)
+ {
+ print_red_text(pad, line++, 1, "Error opening file: %s", full_file_path);
+ *content_line = line;
+ return;
+ }
+
+ while (fgets(buffer, sizeof(buffer), file))
+ {
+ buffer[strcspn(buffer, "\n")] = '\0';
+
+ start = 0;
+ while (start < (int)strlen(buffer))
+ {
+ break_point = start + max_x;
+ if (break_point < (int)strlen(buffer))
+ {
+ while (break_point > start && !isspace(buffer[break_point]))
+ break_point--;
+
+ if (break_point == start)
+ break_point = start + max_x;
+ }
+ else
+ {
+ break_point = strlen(buffer);
+ }
+
+ strncpy(temp, buffer + start, break_point - start);
+ temp[break_point - start] = '\0';
+
+ mvwprintw(pad, line++, 2, "%s", temp);
+
+ start = (buffer[break_point] == ' ') ? break_point + 1 : break_point;
+ }
+ }
+
+ line++;
+ mvwprintw(pad, line++, 2, "-----------------EOF-------------------");
+
+ *content_line = line;
+ fclose(file);
+}
\ No newline at end of file
diff --git a/tools/displaytop/src/populate.c b/tools/displaytop/src/populate.c
index 0872b0b43..fe8cd215c 100644
--- a/tools/displaytop/src/populate.c
+++ b/tools/displaytop/src/populate.c
@@ -29,4 +29,5 @@ void populate_data(void)
root = create_node("Display Top", display_summary, NULL);
initialize_display_config();
+ initialize_display_debugfs();
}
diff --git a/tools/displaytop/src/populate_display_debugfs.c b/tools/displaytop/src/populate_display_debugfs.c
new file mode 100644
index 000000000..494414764
--- /dev/null
+++ b/tools/displaytop/src/populate_display_debugfs.c
@@ -0,0 +1,99 @@
+/*
+ * Copyright © 2025 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include "populate.h"
+#include "utils.h"
+
+static void populate_debugfs_recursive(Node *parent, const char *currentPath)
+{
+ DIR *dir;
+ struct dirent *entry;
+ char full_path[1024];
+ char dir_name_with_asterisk[1024];
+ struct stat pathStat;
+ Node *fileNode;
+ Node *dirNode;
+
+ dir = opendir(currentPath);
+ if (!dir)
+ {
+ log_message(LOG_ERROR, "Failed to open directory: %s", currentPath);
+ return;
+ }
+
+ while ((entry = readdir(dir)) != NULL)
+ {
+ if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
+ continue;
+
+ snprintf(full_path, sizeof(full_path), "%s/%s", currentPath, entry->d_name);
+
+ if (stat(full_path, &pathStat) == -1)
+ {
+ log_message(LOG_WARNING, "Could not stat path: %s", full_path);
+ continue;
+ }
+
+ if (S_ISREG(pathStat.st_mode))
+ {
+ fileNode = create_node(entry->d_name, display_debugfs_file, parent);
+ add_child(parent, fileNode);
+ }
+ else if (S_ISDIR(pathStat.st_mode))
+ {
+ snprintf(dir_name_with_asterisk, sizeof(dir_name_with_asterisk), "%s*", entry->d_name);
+
+ dirNode = create_node(dir_name_with_asterisk, NULL, parent);
+ populate_debugfs_recursive(dirNode, full_path);
+ add_child(parent, dirNode);
+ }
+ }
+
+ closedir(dir);
+}
+
+static void populate_debugfs(Node *parent)
+{
+ char *selected_path = find_debugfs_dir();
+ if (!selected_path)
+ return;
+
+ populate_debugfs_recursive(parent, selected_path);
+ free(selected_path);
+}
+
+void initialize_display_debugfs(void)
+{
+ Node *display_debugfs;
+
+ display_debugfs = create_node("Display Debugfs", NULL, root);
+ populate_debugfs(display_debugfs);
+
+ if (display_debugfs->children_size == 0)
+ {
+ free(display_debugfs);
+ return;
+ }
+
+ add_child(root, display_debugfs);
+}
diff --git a/tools/displaytop/src/utils_driver.c b/tools/displaytop/src/utils_driver.c
index 7b24d2f41..b09e2abba 100644
--- a/tools/displaytop/src/utils_driver.c
+++ b/tools/displaytop/src/utils_driver.c
@@ -187,3 +187,57 @@ void check_and_load_driver(void)
show_driver_menu();
}
}
+
+char *find_debugfs_dir(void)
+{
+ DIR *dir;
+ struct dirent *entry;
+ char *selected_path = NULL;
+
+ dir = opendir(DEBUGFS_DRI_PATH);
+ if (!dir)
+ {
+ log_message(LOG_ERROR, "Failed to open debugfs dri directory");
+ return NULL;
+ }
+
+ while ((entry = readdir(dir)) != NULL)
+ {
+ if (strncmp(entry->d_name, "0000:", 5) == 0)
+ {
+ selected_path = malloc(512);
+ if (!selected_path)
+ {
+ log_message(LOG_ERROR, "Memory allocation failed");
+ closedir(dir);
+ return NULL;
+ }
+
+ snprintf(selected_path, 512, "%s/%s", DEBUGFS_DRI_PATH, entry->d_name);
+ closedir(dir);
+ return selected_path;
+ }
+ }
+
+ rewinddir(dir);
+ while ((entry = readdir(dir)) != NULL)
+ {
+ if (!isdigit(entry->d_name[0]))
+ continue;
+
+ selected_path = malloc(512);
+ if (!selected_path)
+ {
+ log_message(LOG_ERROR, "Memory allocation failed");
+ closedir(dir);
+ return NULL;
+ }
+
+ snprintf(selected_path, 512, "%s/%s", DEBUGFS_DRI_PATH, entry->d_name);
+ log_message(LOG_INFO, "Using debugfs path: %s", selected_path);
+ break;
+ }
+
+ closedir(dir);
+ return selected_path;
+}
\ No newline at end of file
--
2.43.0
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