Add a small diagnostic utility built on the new drmModeGetCrtcList() API. It prints the total number of CRTCs, how many are free vs in use, and a per-CRTC line with state, scanout framebuffer and active mode.
Built like the other tests/ utilities (drmdevice, modeprint); it is a human-facing tool and is intentionally not registered as a meson test, since correctness is covered by the drmmode_crtc_list_ult suite. Signed-off-by: Arun R Murthy <[email protected]> --- tests/crtclist.c | 116 ++++++++++++++++++++++++++++++++++++++++++++++ tests/meson.build | 9 ++++ 2 files changed, 125 insertions(+) create mode 100644 tests/crtclist.c diff --git a/tests/crtclist.c b/tests/crtclist.c new file mode 100644 index 00000000..7ac16853 --- /dev/null +++ b/tests/crtclist.c @@ -0,0 +1,116 @@ +/* + * Copyright © 2026 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 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. + */ + +/* + * crtclist - inspect CRTC usage on a DRM device via drmModeGetCrtcList(). + * + * Prints the total number of CRTCs, how many are free vs in use, and a + * per-CRTC line showing state, scanout framebuffer and active mode. Useful + * for compositor bring-up to see which CRTCs are available. + * + * Usage: crtclist [/dev/dri/cardN] (defaults to the first KMS node) + */ + +#include <fcntl.h> +#include <stdio.h> +#include <unistd.h> + +#include <xf86drm.h> +#include <xf86drmMode.h> + +static int open_kms_node(void) +{ + char path[64]; + int i; + + for (i = 0; i < 16; i++) { + int fd; + + snprintf(path, sizeof(path), "/dev/dri/card%d", i); + fd = open(path, O_RDWR | O_CLOEXEC); + if (fd < 0) + continue; + if (drmIsKMS(fd)) { + printf("Using %s\n", path); + return fd; + } + close(fd); + } + return -1; +} + +int main(int argc, char **argv) +{ + drmModeCrtcListPtr list; + int fd, i; + + if (argc > 1) + fd = open(argv[1], O_RDWR | O_CLOEXEC); + else + fd = open_kms_node(); + + if (fd < 0) { + fprintf(stderr, "No accessible KMS DRM device (try running as root).\n"); + return 1; + } + + list = drmModeGetCrtcList(fd); + if (!list) { + fprintf(stderr, "drmModeGetCrtcList() failed\n"); + close(fd); + return 1; + } + + printf("Total CRTCs : %d\n", list->count); + printf("Available : %d\n", list->count_available); + printf("In use : %d\n\n", list->count - list->count_available); + + printf("%-5s %-8s %-13s %-8s %s\n", + "idx", "crtc_id", "state", "fb_id", "mode"); + printf("-------------------------------------------------------\n"); + for (i = 0; i < list->count; i++) { + drmModeCrtcInfoPtr c = &list->crtcs[i]; + const char *state; + + if (c->in_use) + state = "IN USE"; + else if (c->driver_active) + state = "ACTIVE"; + else + state = "FREE"; + + printf("%-5d %-8u %-13s %-8u ", + c->index, c->crtc_id, state, c->buffer_id); + if (c->in_use) + printf("%ux%u @ %uHz (%s)\n", + c->width, c->height, c->mode.vrefresh, + c->mode.name); + else if (c->driver_active) + printf("(active in hardware, not enabled via KMS)\n"); + else + printf("-\n"); + } + + drmModeFreeCrtcList(list); + close(fd); + return 0; +} diff --git a/tests/meson.build b/tests/meson.build index ac9e66b0..9c98bc2b 100644 --- a/tests/meson.build +++ b/tests/meson.build @@ -69,6 +69,15 @@ drmdevice = executable( install : with_install_tests, ) +crtclist = executable( + 'crtclist', + files('crtclist.c'), + include_directories : [inc_root, inc_drm], + link_with : libdrm, + c_args : libdrm_c_args, + install : with_install_tests, +) + test('hash', hash) test('drmsl', drmsl) test('drmdevice', drmdevice) -- 2.25.1
