/* 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);
}
