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-rw-r--r--src/blueshift_drm_c.c446
1 files changed, 446 insertions, 0 deletions
diff --git a/src/blueshift_drm_c.c b/src/blueshift_drm_c.c
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+++ b/src/blueshift_drm_c.c
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+/**
+ * Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <alloca.h>
+
+#ifndef O_CLOEXEC
+ #define O_CLOEXEC 02000000
+#endif
+
+/* Requires video group */
+#include <xf86drm.h>
+#include <xf86drmMode.h>
+
+
+
+/**
+ * File descriptor for the DRM connection
+ */
+static int drm_fd;
+
+/**
+ * DRM mode resources
+ */
+static drmModeRes* drm_res = NULL;
+
+/**
+ * Connector information
+ */
+static drmModeConnector* connector = NULL;
+
+
+
+/**
+ * Get the number of cards present on the system
+ *
+ * @return The number of cards present on the system
+ */
+int blueshift_drm_card_count()
+{
+ long maxlen = strlen(DRM_DIR_NAME) + strlen(DRM_DEV_NAME) + 10;
+ char* pathname = alloca(maxlen * sizeof(char));
+ int count = 0;
+ struct stat attr;
+
+ for (;;)
+ {
+ sprintf(pathname, DRM_DEV_NAME, DRM_DIR_NAME, count);
+ if (stat(pathname, &attr))
+ break;
+ count++;
+ }
+
+ return count;
+}
+
+
+/**
+ * Open connection to a graphics card
+ *
+ * @param card The index of the graphics card
+ * @return Zero on success
+ */
+int blueshift_drm_open(int card)
+{
+ long maxlen = strlen(DRM_DIR_NAME) + strlen(DRM_DEV_NAME) + 10;
+ char* pathname = alloca(maxlen * sizeof(char));
+
+ sprintf(pathname, DRM_DEV_NAME, DRM_DIR_NAME, card);
+
+ drm_fd = open(pathname, O_RDWR | O_CLOEXEC);
+ if (drm_fd < 0)
+ {
+ perror("open");
+ return 1;
+ }
+
+ return 0;
+}
+
+
+/**
+ * Close connection to the graphics card
+ */
+void blueshift_drm_close()
+{
+ drmModeFreeResources(drm_res);
+ close(drm_fd);
+}
+
+
+/**
+ * Update the resource, required after `blueshift_drm_open`
+ */
+void blueshift_drm_update()
+{
+ if (drm_res)
+ drmModeFreeResources(drm_res);
+
+ drm_res = drmModeGetResources(drm_fd);
+}
+
+
+/**
+ * Return the number of CRTC:s on the opened card
+ *
+ * @return The number of CRTC:s on the opened card
+ */
+int blueshift_drm_crtc_count()
+{
+ return drm_res->count_crtcs;
+}
+
+
+/**
+ * Return the number of connectors on the opened card
+ *
+ * @return The number of connectors on the opened card
+ */
+int blueshift_drm_connector_count()
+{
+ return drm_res->count_connectors;
+}
+
+
+/**
+ * Return the size of the gamma ramps on a CRTC
+ *
+ * @param crtc_index The index of the CRTC
+ * @return The size of the gamma ramps on a CRTC
+ */
+int blueshift_drm_gamma_size(int crtc_index)
+{
+ drmModeCrtc* crtc = drmModeGetCrtc(drm_fd, *(drm_res->crtcs + crtc_index));
+ int gamma_size;
+
+ gamma_size = crtc->gamma_size;
+ drmModeFreeCrtc(crtc);
+
+ return gamma_size;
+}
+
+
+/**
+ * Acquire information about a connector
+ *
+ * @param connector_index The index of the connector
+ */
+void blueshift_drm_open_connector(int connector_index)
+{
+ connector = drmModeGetConnector(drm_fd, *(drm_res->connectors + connector_index));
+}
+
+
+/**
+ * Release information about the connector
+ */
+void blueshift_drm_close_connector()
+{
+ drmModeFreeConnector(connector);
+}
+
+
+/* Accurate dimension on area not covered by the edges */
+
+/**
+ * Get the physical width the monitor connected to the connector
+ *
+ * @return The physical width of the monitor in millimetres, 0 if unknown or not connected
+ */
+int blueshift_drm_get_width()
+{
+ return connector->mmWidth;
+}
+
+
+/**
+ * Get the physical height the monitor connected to the connector
+ *
+ * @return The physical height of the monitor in millimetres, 0 if unknown or not connected
+ */
+int blueshift_drm_get_height()
+{
+ return connector->mmHeight;
+}
+
+
+/**
+ * Get whether a monitor is connected to a connector
+ *
+ * @return 1 if there is a connection, 0 otherwise, -1 if unknown
+ */
+int blueshift_drm_is_connected()
+{
+ switch (connector->connection)
+ {
+ case DRM_MODE_CONNECTED:
+ return 1;
+ case DRM_MODE_DISCONNECTED:
+ return 0;
+ case DRM_MODE_UNKNOWNCONNECTION:
+ default:
+ return -1;
+ }
+}
+
+
+/**
+ * Get the index of the CRTC of the monitor connected to the connector
+ *
+ * @return The index of the CRTC
+ */
+int blueshift_drm_get_crtc()
+{
+ drmModeEncoder* encoder = drmModeGetEncoder(drm_fd, connector->encoder_id);
+ uint32_t crtc_id = encoder->crtc_id;
+ int crtc;
+
+ drmModeFreeEncoder(encoder);
+
+ for (crtc = 0; crtc < drm_res->count_crtcs; crtc++)
+ if (*(drm_res->crtcs + crtc) == crtc_id)
+ return crtc;
+
+ return -1;
+}
+
+
+/**
+ * Get the index of the type of the connector
+ *
+ * @return The connector type by index, 0 for unknown
+ */
+int blueshift_drm_get_connector_type_index()
+{
+ return connector->connector_type;
+}
+
+
+/**
+ * Get the name of the type of the connector
+ *
+ * @return The connector type by name, "Unknown" if not identifiable,
+ * "Unrecognised" if Blueshift does not recognise it.
+ */
+const char* blueshift_drm_get_connector_type_name()
+{
+ static const char* TYPE_NAMES[] = {
+ "Unknown", "VGA", "DVII", "DVID", "DVIA", "Composite", "SVIDEO", "LVDS", "Component",
+ "9PinDIN", "DisplayPort", "HDMIA", "HDMIB", "TV", "eDP", "VIRTUAL", "DSI"};
+
+ int type = connector->connector_type;
+ return (size_t)type < sizeof(TYPE_NAMES) / sizeof(char*) ? TYPE_NAMES[type] : "Unrecognised";
+}
+
+
+/**
+ * Get the current gamma ramps of the
+ *
+ * @param crtc_index The index of the CRTC to read from
+ * @param gamma_size The size a gamma ramp
+ * @param red Storage location for the red gamma ramp
+ * @param green Storage location for the green gamma ramp
+ * @param blue Storage location for the blue gamma ramp
+ * @return Zero on success
+ */
+int blueshift_drm_get_gamma_ramps(int crtc_index, int gamma_size, uint16_t* red, uint16_t* green, uint16_t* blue)
+{
+ int i;
+
+ /* We need to initialise it to avoid valgrind warnings */
+ for (i = 0; i < gamma_size; i++)
+ *(red + i) = *(green + i) = *(blue + i) = 0;
+
+ return drmModeCrtcGetGamma(drm_fd, *(drm_res->crtcs + crtc_index), gamma_size, red, green, blue);
+}
+
+
+/**
+ * Get the extended display identification data for the monitor connected to the connector
+ *
+ * @param edid Storage location for the EDID, it should be 128 bytes, 256 bytes + zero termination if hex
+ * @param size The size allocated to `edid` excluding your zero termination
+ * @param hex Whether to convert to hexadecimal representation, this is preferable
+ * @return The length of the found value, 0 if none, as if hex is false
+ */
+long blueshift_drm_get_edid(char* edid, long size, int hex)
+{
+ long rc = 0;
+ int prop_i;
+ for (prop_i = 0; prop_i < connector->count_props; prop_i++)
+ {
+ drmModePropertyRes* prop = drmModeGetProperty(drm_fd, connector->props[prop_i]);
+ if (!strcmp("EDID", prop->name))
+ {
+ drmModePropertyBlobRes* blob = drmModeGetPropertyBlob(drm_fd, connector->prop_values[prop_i]);
+ if (hex)
+ {
+ rc += blob->length;
+ uint32_t n = size / 2;
+ uint32_t i;
+ if (n < blob->length)
+ n = blob->length;
+ for (i = 0; i < n ; i++)
+ {
+ *(edid + i * 2 + 0) = "0123456789abcdef"[(*((char*)(blob->data) + i) >> 4) & 15];
+ *(edid + i * 2 + 1) = "0123456789abcdef"[(*((char*)(blob->data) + i) >> 0) & 15];
+ }
+ }
+ else
+ memcpy(edid, blob->data, (blob->length < size ? blob->length : size) * sizeof(char));
+ drmModeFreePropertyBlob(blob);
+ prop_i = connector->count_props; /* stop to for loop */
+ }
+ drmModeFreeProperty(prop);
+ }
+ return rc;
+}
+
+
+
+int main(int argc, char** argv)
+{
+ int card_n = blueshift_drm_card_count();
+ int card_i;
+
+ (void) argc;
+ (void) argv;
+
+ printf("Card count: %i\n", card_n);
+ for (card_i = 0; card_i < card_n; card_i++)
+ {
+ int connector_n;
+ int connector_i;
+
+ printf("Card: %i\n", card_i);
+
+ blueshift_drm_open(0);
+ blueshift_drm_update();
+
+ connector_n = blueshift_drm_connector_count();
+
+ printf(" CRTC count: %i\n", blueshift_drm_crtc_count());
+ printf(" Connector count: %i\n", connector_n);
+
+ for (connector_i = 0; connector_i < connector_n; connector_i++)
+ {
+ int crtc;
+
+ blueshift_drm_open_connector(connector_i);
+
+ printf(" Connector: %i\n",
+ connector_i);
+ printf(" Connected: %i\n",
+ blueshift_drm_is_connected());
+ printf(" Connector type: %s (%i)\n",
+ blueshift_drm_get_connector_type_name(),
+ blueshift_drm_get_connector_type_index());
+
+ if (blueshift_drm_is_connected() == 1)
+ {
+ long size = 128;
+ char* edid = malloc((size * 2 + 1) * sizeof(char));
+ long n;
+
+ printf(" Physical size: %i mm by %i mm\n",
+ blueshift_drm_get_width(),
+ blueshift_drm_get_height());
+
+ if ((n = blueshift_drm_get_edid(edid, size, 1)))
+ {
+ if (n > size)
+ {
+ size = n;
+ edid = realloc(edid, (size * 2 + 1) * sizeof(char));
+ blueshift_drm_get_edid(edid, size, 1);
+ }
+ *(edid + n * 2) = 0;
+ printf(" EDID: %s\n", edid);
+ }
+ free(edid);
+
+ if ((crtc = blueshift_drm_get_crtc()) >= 0)
+ {
+ int gamma_size = blueshift_drm_gamma_size(crtc);
+ uint16_t* red = alloca(3 * gamma_size * sizeof(uint16_t));
+ uint16_t* green = red + gamma_size;
+ uint16_t* blue = green + gamma_size;
+
+ printf(" CRTC: %i\n", crtc);
+ printf(" Gamma size: %i\n", gamma_size);
+
+ if (!blueshift_drm_get_gamma_ramps(crtc, gamma_size, red, green, blue))
+ {
+ int j;
+ printf(" Red:");
+ for (j = 0; j < gamma_size; j++)
+ printf(" %u", *(red + j));
+ printf("\n Green:");
+ for (j = 0; j < gamma_size; j++)
+ printf(" %u", *(green + j));
+ printf("\n Blue:");
+ for (j = 0; j < gamma_size; j++)
+ printf(" %u", *(blue + j));
+ printf("\n");
+
+ for (j = 0; j < gamma_size; j++)
+ *(red + j) /= 2;
+ for (j = 0; j < gamma_size; j++)
+ *(green + j) /= 2;
+ for (j = 0; j < gamma_size; j++)
+ *(blue + j) /= 2;
+
+ drmModeCrtcSetGamma(drm_fd, *(drm_res->crtcs + crtc), gamma_size, red, green, blue);
+ /* Fails if inside a graphical environment */
+ }
+ }
+ }
+
+ blueshift_drm_close_connector();
+ }
+ }
+ blueshift_drm_close();
+
+ return 0;
+}
+
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