diff options
Diffstat (limited to 'drmgamma.c')
| -rw-r--r-- | drmgamma.c | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/drmgamma.c b/drmgamma.c new file mode 100644 index 0000000..43adb2e --- /dev/null +++ b/drmgamma.c @@ -0,0 +1,262 @@ +/* See LICENSE file for copyright and license details. */ +#include "common.h" + + +/** + * The number of elements to allocates to a buffer for a DRM device pathname + */ +#define DRM_DEV_NAME_MAX_LEN\ + ((sizeof(DRM_DEV_NAME) + sizeof(DRM_DIR_NAME)) / sizeof(char) + 3 * sizeof(int)) + + + +/** + * Figure out how many graphics cards there are on the system + * + * @return The number of graphics cards on the system + */ +size_t +drm_card_count(void) +{ + char buf[DRM_DEV_NAME_MAX_LEN]; + size_t count = 0; + for (;; count++) { + sprintf(buf, DRM_DEV_NAME, DRM_DIR_NAME, (int)count); + if (access(buf, F_OK) < 0) + return count; + } +} + +/** + * Acquire access to a graphics card + * + * @param index The index of the graphics card + * @param card Graphics card information to fill in + * @return Zero on success, -1 on error + */ +int +drm_card_open(size_t index, drm_card_t *restrict card) +{ + char buf[DRM_DEV_NAME_MAX_LEN]; + int old_errno; + size_t i, n; + + card->fd = -1; + card->res = NULL; + card->connectors = NULL; + card->encoders = NULL; + card->connector_count = 0; + + sprintf(buf, DRM_DEV_NAME, DRM_DIR_NAME, (int)index); + card->fd = open(buf, O_RDWR); + if (card->fd < 0) + goto fail; + + card->res = drmModeGetResources(card->fd); + if (!card->res) + goto fail; + + card->crtc_count = (size_t)(card->res->count_crtcs); + card->connector_count = (size_t)(card->res->count_connectors); + n = card->connector_count; + + card->connectors = calloc(n, sizeof(drmModeConnector*)); + if (!card->connectors) + goto fail; + card->encoders = calloc(n, sizeof(drmModeEncoder*)); + if (!card->encoders) + goto fail; + + for (i = 0; i < n; i++) { + card->connectors[i] = drmModeGetConnector(card->fd, card->res->connectors[i]); + if (!card->connectors[i]) + goto fail; + + if (card->connectors[i]->encoder_id) { + card->encoders[i] = drmModeGetEncoder(card->fd, card->connectors[i]->encoder_id); + if (!card->encoders[i]) + goto fail; + } + } + + return 0; +fail: + old_errno = errno; + drm_card_close(card); + errno = old_errno; + return -1; +} + + +/** + * Release access to a graphics card + * + * @param card The graphics card information + */ +void +drm_card_close(drm_card_t *restrict card) +{ + size_t i, n = card->connector_count; + + if (card->encoders) { + for (i = 0; i < n; i++) + if (card->encoders[i]) + drmModeFreeEncoder(card->encoders[i]); + free(card->encoders); + card->encoders = NULL; + } + + if (card->connectors) { + for (i = 0; i < n; i++) + if (card->connectors[i]) + drmModeFreeConnector(card->connectors[i]); + free(card->connectors); + card->connectors = NULL; + } + + if (card->res) { + drmModeFreeResources(card->res); + card->res = NULL; + } + if (card->fd >= 0) { + close(card->fd); + card->fd = -1; + } +} + + +/** + * Acquire access to a CRT controller + * + * @param index The index of the CRT controller + * @param card The graphics card information + * @param crtc CRT controller information to fill in + * @return Zero on success, -1 on error + */ +int +drm_crtc_open(size_t index, drm_card_t *restrict card, drm_crtc_t *restrict crtc) +{ + drmModePropertyRes *restrict prop; + drmModePropertyBlobRes *restrict blob; + drmModeCrtc *restrict info; + size_t i, j; + int old_errno; + unsigned char c; + + crtc->edid = NULL; + crtc->red = NULL; + crtc->green = NULL; + crtc->blue = NULL; + + crtc->id = card->res->crtcs[index]; + crtc->card = card; + + crtc->connector = NULL; + crtc->encoder = NULL; + for (i = 0; i < card->connector_count; i++) { + if (card->encoders[i]) { + if (card->encoders[i]->crtc_id == crtc->id) { + crtc->connector = card->connectors[i]; + crtc->encoder = card->encoders[i]; + } + } + } + + crtc->connected = crtc->connector && crtc->connector->connection == DRM_MODE_CONNECTED; + + info = drmModeGetCrtc(card->fd, crtc->id); + if (!info) + return -1; + crtc->gamma_stops = (size_t)info->gamma_size; + drmModeFreeCrtc(info); + + /* `calloc` is for some reason required when reading the gamma ramps. */ + crtc->red = calloc(3 * crtc->gamma_stops, sizeof(uint16_t)); + if (!crtc->red) + return -1; + crtc->green = crtc->red + crtc->gamma_stops; + crtc->blue = crtc->green + crtc->gamma_stops; + + if (!crtc->connector) + return 0; + for (i = 0; i < (size_t)crtc->connector->count_props; i++) { + prop = drmModeGetProperty(card->fd, crtc->connector->props[i]); + if (!prop) + continue; + + if (strcmp(prop->name, "EDID")) + goto free_prop; + + blob = drmModeGetPropertyBlob(card->fd, (uint32_t)crtc->connector->prop_values[i]); + i = (size_t)crtc->connector->count_props; + if (!blob || !blob->data) + goto free_blob; + + crtc->edid = malloc((blob->length * 2 + 1) * sizeof(char)); + if (!crtc->edid) { + old_errno = errno; + drmModeFreePropertyBlob(blob); + drmModeFreeProperty(prop); + free(crtc->red); + crtc->red = NULL; + errno = old_errno; + return -1; + } + for (j = 0; j < blob->length; j++) { + c = ((unsigned char *)blob->data)[j]; + crtc->edid[j * 2 + 0] = "0123456789ABCDEF"[(c >> 4) & 15]; + crtc->edid[j * 2 + 1] = "0123456789ABCDEF"[(c >> 0) & 15]; + } + crtc->edid[blob->length * 2] = '\0'; + + free_blob: + if (blob) + drmModeFreePropertyBlob(blob); + + free_prop: + drmModeFreeProperty(prop); + } + + return 0; +} + + +/** + * Release access to a CRT controller + * + * @param crtc The CRT controller information to fill in + */ +void +drm_crtc_close(drm_crtc_t *restrict crtc) +{ + free(crtc->edid); + free(crtc->red); + crtc->edid = NULL; + crtc->red = NULL; +} + + +/** + * Read the gamma ramps for a CRT controller + * + * @param crtc CRT controller information + * @return Zero on success, -1 on error + */ +int +drm_get_gamma(drm_crtc_t *restrict crtc) +{ + return -!!drmModeCrtcGetGamma(crtc->card->fd, crtc->id, (uint32_t)crtc->gamma_stops, crtc->red, crtc->green, crtc->blue); +} + + +/** + * Apply gamma ramps for a CRT controller + * + * @param crtc CRT controller information + * @return Zero on success, -1 on error + */ +int +drm_set_gamma(drm_crtc_t *restrict crtc) +{ + return -!!drmModeCrtcSetGamma(crtc->card->fd, crtc->id, (uint32_t)crtc->gamma_stops, crtc->red, crtc->green, crtc->blue); +} |