From: Kent Gibson <warthog618@gmail.com>
To: linux-gpio@vger.kernel.org, brgl@bgdev.pl
Cc: Kent Gibson <warthog618@gmail.com>
Subject: [libgpiod][PATCH] tests: add enable_debounce_then_edge_detection
Date: Tue, 14 May 2024 00:00:31 +0800 [thread overview]
Message-ID: <20240513160031.309139-1-warthog618@gmail.com> (raw)
A bug was recently discovered in the kernel that can result in the edge
event fifo not being correctly initialised and stack contents being
returned in edge events. The trigger for the bug is requesting a line with
debounce, but not edge detection, and then reconfiguring the line to
enable edge detection.
Add a test case that triggers the bug. This will fail on kernels that
do not contain the fix for the bug. The test is located in a new test
file, tests-kernel-uapi.c, intended to contain tests specifically
testing some aspect of the kernel uAPI, not libgpiod itself.
Signed-off-by: Kent Gibson <warthog618@gmail.com>
---
tests/Makefile.am | 1 +
tests/tests-kernel-uapi.c | 112 ++++++++++++++++++++++++++++++++++++++
2 files changed, 113 insertions(+)
create mode 100644 tests/tests-kernel-uapi.c
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 0680d5e..a5e1fe0 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -24,6 +24,7 @@ gpiod_test_SOURCES = \
tests-chip-info.c \
tests-edge-event.c \
tests-info-event.c \
+ tests-kernel-uapi.c \
tests-line-config.c \
tests-line-info.c \
tests-line-request.c \
diff --git a/tests/tests-kernel-uapi.c b/tests/tests-kernel-uapi.c
new file mode 100644
index 0000000..453237c
--- /dev/null
+++ b/tests/tests-kernel-uapi.c
@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+// SPDX-FileCopyrightText: 2021-2022 Bartosz Golaszewski <bartekgola@gmail.com>
+// SPDX-FileCopyrightText: 2024 Kent Gibson <warthog618@gmail.com>
+
+#include <glib.h>
+#include <gpiod.h>
+#include <poll.h>
+
+#include "gpiod-test.h"
+#include "gpiod-test-helpers.h"
+#include "gpiod-test-sim.h"
+
+#define GPIOD_TEST_GROUP "kernel-uapi"
+
+static gpointer falling_and_rising_edge_events(gpointer data)
+{
+ GPIOSimChip *sim = data;
+
+ /*
+ * needs to be as long as several system timer ticks or resulting
+ * pulse width is unreliable and may get filtered by debounce.
+ */
+ g_usleep(50000);
+
+ g_gpiosim_chip_set_pull(sim, 2, G_GPIOSIM_PULL_UP);
+
+ g_usleep(50000);
+
+ g_gpiosim_chip_set_pull(sim, 2, G_GPIOSIM_PULL_DOWN);
+
+ return NULL;
+}
+
+GPIOD_TEST_CASE(enable_debounce_then_edge_detection)
+{
+ static const guint offset = 2;
+
+ g_autoptr(GPIOSimChip) sim = g_gpiosim_chip_new("num-lines", 8, NULL);
+ g_autoptr(struct_gpiod_chip) chip = NULL;
+ g_autoptr(struct_gpiod_line_settings) settings = NULL;
+ g_autoptr(struct_gpiod_line_config) line_cfg = NULL;
+ g_autoptr(struct_gpiod_line_request) request = NULL;
+ g_autoptr(GThread) thread = NULL;
+ g_autoptr(struct_gpiod_edge_event_buffer) buffer = NULL;
+ struct gpiod_edge_event *event;
+ guint64 ts_rising, ts_falling;
+ gint ret;
+
+ chip = gpiod_test_open_chip_or_fail(g_gpiosim_chip_get_dev_path(sim));
+ settings = gpiod_test_create_line_settings_or_fail();
+ line_cfg = gpiod_test_create_line_config_or_fail();
+ buffer = gpiod_test_create_edge_event_buffer_or_fail(64);
+
+ gpiod_line_settings_set_direction(settings, GPIOD_LINE_DIRECTION_INPUT);
+ gpiod_line_settings_set_debounce_period_us(settings, 10);
+ gpiod_test_line_config_add_line_settings_or_fail(line_cfg, &offset, 1,
+ settings);
+ request = gpiod_test_chip_request_lines_or_fail(chip, NULL, line_cfg);
+
+ gpiod_line_settings_set_edge_detection(settings, GPIOD_LINE_EDGE_BOTH);
+ gpiod_test_line_config_add_line_settings_or_fail(line_cfg, &offset, 1,
+ settings);
+ gpiod_test_line_request_reconfigure_lines_or_fail(request, line_cfg);
+
+ thread = g_thread_new("request-release",
+ falling_and_rising_edge_events, sim);
+ g_thread_ref(thread);
+
+ /* First event. */
+
+ ret = gpiod_line_request_wait_edge_events(request, 1000000000);
+ g_assert_cmpint(ret, >, 0);
+ gpiod_test_join_thread_and_return_if_failed(thread);
+
+ ret = gpiod_line_request_read_edge_events(request, buffer, 1);
+ g_assert_cmpint(ret, ==, 1);
+ gpiod_test_join_thread_and_return_if_failed(thread);
+
+ g_assert_cmpuint(gpiod_edge_event_buffer_get_num_events(buffer), ==, 1);
+ event = gpiod_edge_event_buffer_get_event(buffer, 0);
+ g_assert_nonnull(event);
+ gpiod_test_join_thread_and_return_if_failed(thread);
+
+ g_assert_cmpint(gpiod_edge_event_get_event_type(event), ==,
+ GPIOD_EDGE_EVENT_RISING_EDGE);
+ g_assert_cmpuint(gpiod_edge_event_get_line_offset(event), ==, 2);
+ ts_rising = gpiod_edge_event_get_timestamp_ns(event);
+
+ /* Second event. */
+
+ ret = gpiod_line_request_wait_edge_events(request, 1000000000);
+ g_assert_cmpint(ret, >, 0);
+ gpiod_test_join_thread_and_return_if_failed(thread);
+
+ ret = gpiod_line_request_read_edge_events(request, buffer, 1);
+ g_assert_cmpint(ret, ==, 1);
+ gpiod_test_join_thread_and_return_if_failed(thread);
+
+ g_assert_cmpuint(gpiod_edge_event_buffer_get_num_events(buffer), ==, 1);
+ event = gpiod_edge_event_buffer_get_event(buffer, 0);
+ g_assert_nonnull(event);
+ gpiod_test_join_thread_and_return_if_failed(thread);
+
+ g_assert_cmpint(gpiod_edge_event_get_event_type(event), ==,
+ GPIOD_EDGE_EVENT_FALLING_EDGE);
+ g_assert_cmpuint(gpiod_edge_event_get_line_offset(event), ==, 2);
+ ts_falling = gpiod_edge_event_get_timestamp_ns(event);
+
+ g_thread_join(thread);
+
+ g_assert_cmpuint(ts_falling, >, ts_rising);
+}
--
2.39.2
next reply other threads:[~2024-05-13 16:00 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-13 16:00 Kent Gibson [this message]
2024-05-15 9:01 ` [libgpiod][PATCH] tests: add enable_debounce_then_edge_detection Bartosz Golaszewski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240513160031.309139-1-warthog618@gmail.com \
--to=warthog618@gmail.com \
--cc=brgl@bgdev.pl \
--cc=linux-gpio@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).