/**
* libgamma — Display server abstraction layer for gamma ramp adjustments
* Copyright © 2014 Mattias Andrée (maandree@member.fsf.org)
*
* This library 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 library 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef HAVE_GAMMA_METHOD_LINUX_DRM
# error Compiling gamma-linux-drm.c without HAVE_GAMMA_METHOD_LINUX_DRM
#endif
#define _GNU_SOURCE
#include "gamma-linux-drm.h"
#include "libgamma-error.h"
#include "edid.h"
#include <limits.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <grp.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <inttypes.h>
#include <xf86drm.h>
#include <xf86drmMode.h>
#ifndef O_CLOEXEC
# define O_CLOEXEC 02000000
#endif
#ifndef NGROUPS_MAX
# define NGROUPS_MAX 65536
#endif
#ifndef PATH_MAX
# define PATH_MAX 4096
#endif
/**
* Graphics card data for the Direct Rendering Manager adjustment method
*/
typedef struct libgamma_drm_card_data
{
/**
* File descriptor for the connection to the graphics card
*/
int fd;
/**
* The graphics card's mode resources
*/
drmModeRes* res;
/**
* Resources for open connectors
*/
drmModeConnector** connectors;
/**
* Resources for open encoders
*/
drmModeEncoder** encoders;
} libgamma_drm_card_data_t;
/**
* Return the capabilities of the adjustment method
*
* @param this The data structure to fill with the method's capabilities
*/
void libgamma_linux_drm_method_capabilities(libgamma_method_capabilities_t* restrict this)
{
this->crtc_information = CRTC_INFO_EDID
| CRTC_INFO_WIDTH_MM
| CRTC_INFO_HEIGHT_MM
| CRTC_INFO_WIDTH_MM_EDID
| CRTC_INFO_HEIGHT_MM_EDID
| CRTC_INFO_GAMMA_SIZE
| CRTC_INFO_GAMMA_DEPTH
| CRTC_INFO_SUBPIXEL_ORDER
| CRTC_INFO_ACTIVE
| CRTC_INFO_CONNECTOR_NAME
| CRTC_INFO_CONNECTOR_TYPE
| CRTC_INFO_GAMMA;
this->default_site_known = 1;
this->multiple_sites = 0;
this->multiple_partitions = 1;
this->multiple_crtcs = 1;
this->partitions_are_graphics_cards = 1;
this->site_restore = 0;
this->partition_restore = 0;
this->crtc_restore = 0;
this->identical_gamma_sizes = 1;
this->fixed_gamma_size = 0;
this->fixed_gamma_depth = 1;
this->real = 1;
this->fake = 0;
}
/**
* Initialise an allocated site state
*
* @param this The site state to initialise
* @param site The site identifier, unless it is `NULL` it must a
* `free`:able. One the state is destroyed the library
* will attempt to free it. There you should not free
* it yourself, and it must not be a string constant
* or allocate on the stack. Note however that it will
* not be free:d if this function fails.
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_site_initialise(libgamma_site_state_t* restrict this,
char* restrict site)
{
char pathname[PATH_MAX];
struct stat _attr;
if (site != NULL)
return LIBGAMMA_NO_SUCH_SITE;
/* Count the number of available graphics cards by
* stat:ing there existence in an API filesystem. */
this->partitions_available = 0;
for (;;)
{
snprintf(pathname, sizeof(pathname) / sizeof(char),
DRM_DEV_NAME, DRM_DIR_NAME, (int)(this->partitions_available));
if (stat(pathname, &_attr))
break;
if (this->partitions_available++ > INT_MAX)
return LIBGAMMA_IMPOSSIBLE_AMOUNT;
}
return 0;
}
/**
* Release all resources held by a site state
*
* @param this The site state
*/
void libgamma_linux_drm_site_destroy(libgamma_site_state_t* restrict this)
{
(void) this;
}
/**
* Restore the gamma ramps all CRTCS with a site to the system settings
*
* @param this The site state
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_site_restore(libgamma_site_state_t* restrict this)
{
(void) this;
return errno = ENOTSUP, LIBGAMMA_ERRNO_SET;
}
/**
* Initialise an allocated partition state
*
* @param this The partition state to initialise
* @param site The site state for the site that the partition belongs to
* @param partition The the index of the partition within the site
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_partition_initialise(libgamma_partition_state_t* restrict this,
libgamma_site_state_t* restrict site, size_t partition)
{
int rc = 0;
libgamma_drm_card_data_t* data;
char pathname[PATH_MAX];
(void) site;
/* Check for partition index overflow. */
if (partition > INT_MAX)
return LIBGAMMA_NO_SUCH_PARTITION;
/* Allocate and initialise graphics card data. */
this->data = NULL;
data = malloc(sizeof(libgamma_drm_card_data_t));
if (data == NULL)
return LIBGAMMA_ERRNO_SET;
data->fd = -1;
data->res = NULL;
/* Get the pathname for the graphics card. */
snprintf(pathname, sizeof(pathname) / sizeof(char),
DRM_DEV_NAME, DRM_DIR_NAME, (int)partition);
/* Acquire access to the graphics card. */
data->fd = open(pathname, O_RDWR | O_CLOEXEC);
if (data->fd < 0)
{
if ((errno == ENXIO) || (errno == ENODEV))
rc = LIBGAMMA_NO_SUCH_PARTITION;
else if (errno == EACCES)
{
struct stat attr;
int r;
r = stat(pathname, &attr);
rc = LIBGAMMA_NO_SUCH_PARTITION;
#define __test(R, W) ((attr.st_mode & (R | W)) == (R | W))
if (r)
rc = errno == EACCES ? LIBGAMMA_NO_SUCH_PARTITION : LIBGAMMA_ERRNO_SET;
else if ((attr.st_uid == geteuid() && __test(S_IRUSR, S_IWUSR)) ||
(attr.st_gid == getegid() && __test(S_IRGRP, S_IWGRP)) ||
__test(S_IROTH, S_IWOTH))
rc = LIBGAMMA_DEVICE_ACCESS_FAILED;
else if (attr.st_gid == 0 /* root group */ || __test(S_IRGRP, S_IWGRP))
rc = LIBGAMMA_DEVICE_RESTRICTED;
else
{
gid_t supplemental_groups[NGROUPS_MAX];
struct group* group;
int i, n;
n = getgroups(NGROUPS_MAX, supplemental_groups);
if (n < 0)
{
rc = LIBGAMMA_ERRNO_SET;
goto fail_data;
}
for (i = 0; i < n; i++)
if (supplemental_groups[i] == attr.st_gid)
break;
if (i != n)
{
rc = LIBGAMMA_DEVICE_ACCESS_FAILED;
goto fail_data;
}
rc = LIBGAMMA_DEVICE_REQUIRE_GROUP;
errno = 0;
group = getgrgid(attr.st_gid); /* TODO: Not thread-safe. */
libgamma_group_gid = attr.st_gid;
libgamma_group_name = group != NULL ? group->gr_name : NULL;
}
#undef __test
}
else
rc = LIBGAMMA_ERRNO_SET;
goto fail_data;
}
/* Acquire mode resources. */
data->res = drmModeGetResources(data->fd);
if (data->res == NULL)
{
rc = LIBGAMMA_ACQUIRING_MODE_RESOURCES_FAILED;
goto fail_fd;
}
/* Get the number of CRTC:s that are available in the partition. */
if (data->res->count_crtcs < 0)
{
rc = LIBGAMMA_NEGATIVE_CRTC_COUNT;
goto fail_res;
}
this->crtcs_available = (size_t)(data->res->count_crtcs);
return 0;
fail_res:
drmModeFreeResources(data->res);
fail_fd:
close(data->fd);
fail_data:
free(data);
return rc;
}
/**
* Release all connectors and encoders
*
* @param this The graphics card data
*/
static void release_connectors_and_encoders(libgamma_drm_card_data_t* restrict this)
{
size_t i, n;
if (this->encoders != NULL)
for (i = 0, n = (size_t)(this->res->count_connectors); i < n; i++)
if (this->encoders[i] != NULL)
drmModeFreeEncoder(this->encoders[i]);
free(this->encoders);
this->encoders = NULL;
if (this->connectors != NULL)
for (i = 0, n = (size_t)(this->res->count_connectors); i < n; i++)
if (this->connectors[i] != NULL)
drmModeFreeConnector(this->connectors[i]);
free(this->connectors);
this->connectors = NULL;
}
/**
* Release all resources held by a partition state
*
* @param this The partition state
*/
void libgamma_linux_drm_partition_destroy(libgamma_partition_state_t* restrict this)
{
libgamma_drm_card_data_t* restrict data = this->data;
release_connectors_and_encoders(data);
if (data->res != NULL)
drmModeFreeResources(data->res);
if (data->fd >= 0)
close(data->fd);
free(data);
}
/**
* Restore the gamma ramps all CRTCS with a partition to the system settings
*
* @param this The partition state
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_partition_restore(libgamma_partition_state_t* restrict this)
{
(void) this;
return errno = ENOTSUP, LIBGAMMA_ERRNO_SET;
}
/**
* Initialise an allocated CRTC state
*
* @param this The CRTC state to initialise
* @param partition The partition state for the partition that the CRTC belongs to
* @param crtc The the index of the CRTC within the site
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_crtc_initialise(libgamma_crtc_state_t* restrict this,
libgamma_partition_state_t* restrict partition, size_t crtc)
{
libgamma_drm_card_data_t* restrict card;
uint32_t crtc_id;
if (crtc >= partition->crtcs_available)
return LIBGAMMA_NO_SUCH_CRTC;
card = partition->data;
crtc_id = card->res->crtcs[crtc];
this->data = (void*)(size_t)crtc_id;
return 0;
}
/**
* Release all resources held by a CRTC state
*
* @param this The CRTC state
*/
void libgamma_linux_drm_crtc_destroy(libgamma_crtc_state_t* restrict this)
{
(void) this;
}
/**
* Restore the gamma ramps for a CRTC to the system settings for that CRTC
*
* @param this The CRTC state
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_crtc_restore(libgamma_crtc_state_t* restrict this)
{
(void) this;
return errno = ENOTSUP, LIBGAMMA_ERRNO_SET;
}
/**
* Find the connector that a CRTC belongs to
*
* @param this The CRTC state
* @param error Output of the error value to store of error report fields for data that requires the connector
'* @return The CRTC's conncetor, `NULL` on error
*/
static drmModeConnector* find_connector(libgamma_crtc_state_t* restrict this, int* error)
{
uint32_t crtc_id = (uint32_t)(size_t)(this->data);
libgamma_drm_card_data_t* restrict card = this->partition->data;
size_t i, n = (size_t)(card->res->count_connectors);
/* Open connectors and encoders if not already opened. */
if (card->connectors == NULL)
{
/* We use calloc so all non-loaded elements are `NULL` after an error. */
if ((card->connectors = calloc(n, sizeof(drmModeConnector*))) == NULL)
goto fail;
if ((card->encoders = calloc(n, sizeof(drmModeEncoder*))) == NULL)
goto fail;
for (i = 0; i < n; i++)
if (((card->connectors[i] = drmModeGetConnector(card->fd, card->res->connectors[i])) == NULL) ||
((card->encoders[i] = drmModeGetEncoder(card->fd, card->connectors[i]->encoder_id)) == NULL))
goto fail;
}
/* Find connector. */
*error = 0;
for (i = 0; i < n; i++)
if (card->encoders[i]->crtc_id == crtc_id)
return card->connectors[i];
*error = LIBGAMMA_CONNECTOR_UNKNOWN;
return NULL;
fail:
*error = errno;
release_connectors_and_encoders(card);
return NULL;
}
/**
* Get the size of the gamma ramps for a CRTC
*
* @param out Instance of a data structure to fill with the information about the CRTC
* @param crtc The state of the CRTC whose information should be read
* @return The value stored in `out->gamma_size_error`
*/
static int get_gamma_ramp_size(libgamma_crtc_information_t* restrict out, const libgamma_crtc_state_t* restrict crtc)
{
libgamma_drm_card_data_t* restrict card = crtc->partition->data;
uint32_t crtc_id = card->res->crtcs[crtc->crtc];
drmModeCrtc* restrict crtc_info;
errno = 0;
crtc_info = drmModeGetCrtc(card->fd, crtc_id);
out->gamma_size_error = crtc_info == NULL ? errno : 0;
if (out->gamma_size_error == 0)
{
out->red_gamma_size = (size_t)(crtc_info->gamma_size);
out->green_gamma_size = (size_t)(crtc_info->gamma_size);
out->blue_gamma_size = (size_t)(crtc_info->gamma_size);
out->gamma_size_error = crtc_info->gamma_size < 2 ? LIBGAMMA_SINGLETON_GAMMA_RAMP : 0;
drmModeFreeCrtc(crtc_info);
}
return out->gamma_size_error;
}
/**
* Read information from the CRTC's conncetor
*
* @param crtc The state of the CRTC whose information should be read
* @param out Instance of a data structure to fill with the information about the CRTC
* @param connector The CRTC's connector
* @param fields OR:ed identifiers for the information about the CRTC that should be read
* @return Non-zero if at least on error occured
*/
static int read_connector_data(libgamma_crtc_state_t* restrict crtc, libgamma_crtc_information_t* restrict out,
const drmModeConnector* connector, int32_t fields)
{
const char* connector_name_base = NULL;
/* Get some information that does not require too much work. */
if ((fields & (CRTC_INFO_WIDTH_MM | CRTC_INFO_HEIGHT_MM | CRTC_INFO_CONNECTOR_TYPE |
CRTC_INFO_ACTIVE | CRTC_INFO_SUBPIXEL_ORDER)))
{
/* Get whether or not a monitor is plugged in. */
out->active = connector->connection == DRM_MODE_CONNECTED;
out->active_error = connector->connection == DRM_MODE_UNKNOWNCONNECTION ? LIBGAMMA_STATE_UNKNOWN : 0;
if (out->active == 0)
{
if ((fields & (CRTC_INFO_WIDTH_MM | CRTC_INFO_HEIGHT_MM | CRTC_INFO_SUBPIXEL_ORDER)))
out->width_mm_error = out->height_mm_error = out->subpixel_order_error = LIBGAMMA_NOT_CONNECTED;
goto not_connected;
}
/* Get viewport dimension. */
out->width_mm = connector->mmWidth;
out->height_mm = connector->mmHeight;
/* Get subpixel order. */
#define __select(value) \
case DRM_MODE_SUBPIXEL_##value: out->subpixel_order = LIBGAMMA_SUBPIXEL_ORDER_##value; break
switch (connector->subpixel)
{
__select (UNKNOWN);
__select (HORIZONTAL_RGB);
__select (HORIZONTAL_BGR);
__select (VERTICAL_RGB);
__select (VERTICAL_BGR);
__select (NONE);
default:
out->subpixel_order_error = LIBGAMMA_SUBPIXEL_ORDER_NOT_RECOGNISED;
break;
}
#undef __select
not_connected:
/* Get connector type. */
#define __select(type, name) \
case DRM_MODE_CONNECTOR_##type: out->connector_type = LIBGAMMA_CONNECTOR_TYPE_##type, connector_name_base = name; break
switch (connector->connector_type)
{
#ifndef DRM_MODE_CONNECTOR_VIRTUAL
# define DRM_MODE_CONNECTOR_VIRTUAL 15
#endif
#ifndef DRM_MODE_CONNECTOR_DSI
# define DRM_MODE_CONNECTOR_DSI 16
#endif
__select (Unknown, "Unknown" );
__select (VGA, "VGA" );
__select (DVII, "DVI-I" );
__select (DVID, "DVI-D" );
__select (DVIA, "DVI-A" );
__select (Composite, "Composite");
__select (SVIDEO, "SVIDEO" );
__select (LVDS, "LVDS" );
__select (Component, "Component");
__select (9PinDIN, "DIN" );
__select (DisplayPort, "DP" );
__select (HDMIA, "HDMI-A" );
__select (HDMIB, "HDMI-B" );
__select (TV, "TV" );
__select (eDP, "eDP" );
__select (VIRTUAL, "VIRTUAL" );
__select (DSI, "DSI" );
default:
out->connector_type_error = LIBGAMMA_CONNECTOR_TYPE_NOT_RECOGNISED;
out->connector_name_error = LIBGAMMA_CONNECTOR_TYPE_NOT_RECOGNISED;
break;
}
#undef __select
}
/* Get the connector's name. */
if ((fields & CRTC_INFO_CONNECTOR_NAME) && (out->connector_name_error == 0))
{
libgamma_drm_card_data_t* restrict card = crtc->partition->data;
uint32_t type = connector->connector_type;
size_t i, n = (size_t)(card->res->count_connectors), c = 0;
out->connector_name = malloc((strlen(connector_name_base) + 12) * sizeof(char));
if (out->connector_name == NULL)
return (out->connector_name_error = errno);
for (i = 0; (i < n) && (card->connectors[i] != connector); i++)
if (card->connectors[i]->connector_type == type)
c++;
sprintf(out->connector_name, "%s-" PRIu32, connector_name_base, (uint32_t)(c + 1));
}
/* Did something go wrong? */
return out->subpixel_order_error | out->active_error | out->connector_name_error;
}
/**
* Get the extended display identification data for a monitor
*
* @param crtc The CRTC state
* @param out Instance of a data structure to fill with the information about the CRTC
* @param connector The CRTC's connector
* @reutnr Non-zero on error
*/
static int get_edid(libgamma_crtc_state_t* restrict crtc,
libgamma_crtc_information_t* restrict out, drmModeConnector* connector)
{
libgamma_drm_card_data_t* restrict card = crtc->partition->data;
int prop_n = connector->count_props;
int prop_i;
drmModePropertyRes* prop;
drmModePropertyBlobRes* blob;
for (prop_i = 0; prop_i < prop_n; prop_i++)
{
prop = drmModeGetProperty(card->fd, connector->props[prop_i]);
if (prop == NULL)
continue;
if (!strcmp("EDID", prop->name))
{
blob = drmModeGetPropertyBlob(card->fd, (uint32_t)(connector->prop_values[prop_i]));
if (blob == NULL)
goto fail_blob;
if (blob->data != NULL)
{
out->edid_length = blob->length;
out->edid = malloc(out->edid_length * sizeof(unsigned char));
if (out->edid == NULL)
out->edid_error = errno;
else
memcpy(out->edid, blob->data, (size_t)(out->edid_length) * sizeof(char));
drmModeFreePropertyBlob(blob);
return out->edid == NULL;
}
drmModeFreePropertyBlob(blob);
}
fail_blob:
drmModeFreeProperty(prop);
}
out->edid_error = LIBGAMMA_EDID_NOT_FOUND;
return -1;
}
/**
* Read information about a CRTC
*
* @param this Instance of a data structure to fill with the information about the CRTC
* @param crtc The state of the CRTC whose information should be read
* @param fields OR:ed identifiers for the information about the CRTC that should be read
* @return Zero on success, -1 on error. On error refer to the error reports in `this`.
*/
int libgamma_linux_drm_get_crtc_information(libgamma_crtc_information_t* restrict this,
libgamma_crtc_state_t* restrict crtc, int32_t fields)
{
#define _E(FIELD) ((fields & FIELD) ? LIBGAMMA_CRTC_INFO_NOT_SUPPORTED : 0)
int e = 0;
drmModeConnector* connector;
int require_connector;
int free_edid;
int error;
/* Wipe all error indicators. */
memset(this, 0, sizeof(libgamma_crtc_information_t));
/* We need to free the EDID after us if it is not explicitly requested. */
free_edid = (fields & CRTC_INFO_EDID) == 0;
/* Figure out what fields we need to get the data for to get the data for other fields. */
if ((fields & (CRTC_INFO_WIDTH_MM_EDID | CRTC_INFO_HEIGHT_MM_EDID | CRTC_INFO_GAMMA)))
fields |= CRTC_INFO_EDID;
if ((fields & CRTC_INFO_CONNECTOR_NAME))
fields |= CRTC_INFO_CONNECTOR_TYPE;
if (CRTC_INFO_EDID | CRTC_INFO_WIDTH_MM | CRTC_INFO_HEIGHT_MM | CRTC_INFO_SUBPIXEL_ORDER)
fields |= CRTC_INFO_ACTIVE;
/* Figure out whether we require the connector to get all information we want. */
require_connector = fields & (CRTC_INFO_ACTIVE | CRTC_INFO_CONNECTOR_TYPE);
if (require_connector == 0)
goto cont;
if ((connector = find_connector(crtc, &error)) == NULL)
{
e |= this->width_mm_error = this->height_mm_error
= this->connector_type = this->subpixel_order_error
= this->active_error = this->connector_name_error
= this->edid_error = this->gamma_error
= this->width_mm_edid_error = this->height_mm_edid_error = error;
goto cont;
}
e |= read_connector_data(crtc, this, connector, fields);
if ((fields & CRTC_INFO_EDID) == 0)
goto cont;
if (this->active_error || (this->active == 0))
{
e |= this->edid_error = this->gamma_error
= this->width_mm_edid_error = this->height_mm_edid_error
= LIBGAMMA_NOT_CONNECTED;
goto cont;
}
e |= get_edid(crtc, this, connector);
if (this->edid == NULL)
{
this->gamma_error = this->width_mm_edid_error = this->height_mm_edid_error = this->edid_error;
goto cont;
}
if ((fields & (CRTC_INFO_WIDTH_MM_EDID | CRTC_INFO_HEIGHT_MM_EDID | CRTC_INFO_GAMMA)))
e |= libgamma_parse_edid(this, fields);
cont:
e |= (fields & CRTC_INFO_GAMMA_SIZE) ? get_gamma_ramp_size(this, crtc) : 0;
this->gamma_depth = 16;
e |= this->gamma_support_error = _E(CRTC_INFO_GAMMA_SUPPORT);
/* Free the EDID after us. */
if (free_edid)
{
free(this->edid);
this->edid = NULL;
}
return e ? -1 : 0;
#undef _E
}
/**
* Get current the gamma ramps for a CRTC, 16-bit gamma-depth version
*
* @param this The CRTC state
* @param ramps The gamma ramps to fill with the current values
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_crtc_get_gamma_ramps(libgamma_crtc_state_t* restrict this,
libgamma_gamma_ramps_t* restrict ramps)
{
libgamma_drm_card_data_t* restrict card = this->partition->data;
int r;
#ifdef DEBUG
if ((ramps->red_size != ramps->green_size) ||
(ramps->red_size != ramps->blue_size))
return LIBGAMMA_MIXED_GAMMA_RAMP_SIZE;
#endif
r = drmModeCrtcGetGamma(card->fd, (uint32_t)(size_t)(this->data), (uint32_t)(ramps->red_size),
ramps->red, ramps->green, ramps->blue);
return r ? LIBGAMMA_GAMMA_RAMP_READ_FAILED : 0;
}
/**
* Set the gamma ramps for a CRTC, 16-bit gamma-depth version
*
* @param this The CRTC state
* @param ramps The gamma ramps to apply
* @return Zero on success, otherwise (negative) the value of an
* error identifier provided by this library
*/
int libgamma_linux_drm_crtc_set_gamma_ramps(libgamma_crtc_state_t* restrict this,
libgamma_gamma_ramps_t ramps)
{
libgamma_drm_card_data_t* restrict card = this->partition->data;
int r;
#ifdef DEBUG
if ((ramps.red_size != ramps.green_size) ||
(ramps.red_size != ramps.blue_size))
return LIBGAMMA_MIXED_GAMMA_RAMP_SIZE;
#endif
r = drmModeCrtcSetGamma(card->fd, (uint32_t)(size_t)(this->data),
(uint32_t)(ramps.red_size), ramps.red, ramps.green, ramps.blue);
if (r)
switch (errno)
{
case EACCES:
case EAGAIN:
case EIO:
/* Permission denied errors must be ignored, because we do not
* have permission to do this while a display server is active.
* We are also checking for some other error codes just in case. */
case EBUSY:
case EINPROGRESS:
/* It is hard to find documentation for DRM (in fact all of this is
* just based on the functions names and some testing,) perhaps we
* could get this if we are updating to fast. */
break;
case EBADF:
case ENODEV:
case ENXIO:
/* XXX: I have not actually tested removing my graphics card or,
* monitor but I imagine either of these is what would happen. */
return LIBGAMMA_GRAPHICS_CARD_REMOVED;
default:
return LIBGAMMA_ERRNO_SET;
}
return 0;
}
