pitch.c

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <xf86drm.h>
#include <xf86drmMode.h>
#include <drm_fourcc.h>
#include <libkms.h>

#define LOG(...)                                \
    do {                                        \
        fprintf(stderr, __VA_ARGS__);           \
    } while(0)

int main(int argc, char **argv)
{
    int fd;
    struct kms_driver *kms;
    fd = drmOpen("radeon", NULL);

    LOG("fd: %d\n", fd);
    drmModeResPtr resources;
    uint32_t crtc_id;
    uint32_t connector_id;
    resources = drmModeGetResources(fd);
    crtc_id = resources->crtcs[0];

    drmModeConnectorPtr connector;
    uint32_t width = 0;
    uint32_t height = 0;

    int i;
    for (i = 0; i < resources->count_connectors; i++)
    {
        connector_id = resources->connectors[i];

        LOG("crtc: %d\n", crtc_id);
        LOG("connector: %d\n", connector_id);

        connector = drmModeGetConnector(fd, connector_id);
        LOG("connection: %d\n", connector->connection);
        if (connector->connection == DRM_MODE_DISCONNECTED)
            continue;

        drmModeModeInfo mode;
        mode = connector->modes[0];
        width = mode.hdisplay;
        height = mode.vdisplay;
    }

    /* LOG("modes: %d\n", connector->count_modes); */
    LOG("width x height: %d x %d\n", width, height);

    if (width == 0 || height == 0)
    {
        LOG("no suitable connector found\n");
        exit(1);
    }

    kms_create(fd, &kms);
    unsigned bo_attribs[] = {
        KMS_WIDTH, width,
        KMS_HEIGHT, height,
        KMS_BO_TYPE, KMS_BO_TYPE_SCANOUT_X8R8G8B8,
        KMS_TERMINATE_PROP_LIST
    };
    struct kms_bo *bo;
    kms_bo_create(kms, bo_attribs, &bo);

    uint32_t handles[4];
    uint32_t pitches[4];
    uint32_t offsets[4];
    kms_bo_get_prop(bo, KMS_HANDLE, &handles[0]);
    kms_bo_get_prop(bo, KMS_PITCH, &pitches[0]);
    offsets[0] = 0;

    LOG("pitch: %d\n", pitches[0]);
    LOG("offset: %d\n", offsets[0]);

    int fb_id;

    int format = DRM_FORMAT_XRGB8888;
    LOG("format: %08x\n", format);
    LOG("ARGB8888: %08x\n", DRM_FORMAT_ARGB8888);
    LOG("ABGR8888: %08x\n", DRM_FORMAT_ABGR8888);
    LOG("RGBA8888: %08x\n", DRM_FORMAT_RGBA8888);
    LOG("BGRA8888: %08x\n", DRM_FORMAT_BGRA8888);
    if (drmModeAddFB2(fd, width, height, format,
                      handles, pitches, offsets, &fb_id, 0))
    {
        LOG("addfb2 failed: %m\n");
    }
    else
    {
        LOG("buffer created: %d\n", fb_id);
        drmModeRmFB(fd, fb_id);
    }


    kms_destroy(&kms);

    drmClose(fd);
    return 0;
}