/// \internal
/// <summary>
/// Queries the specified GPU for connected displays and, optionally,
/// returns the list of displays.
/// </summary>
/// <returns><c>true</c>, if at least one display is connected, <c>false</c> otherwise.</returns>
/// <param name="fd">The fd for the GPU to query, obtained through open("/dev/dri/card0").</param>
/// <param name="displays">
/// If not null, this will contain a list <see cref="LinuxDisplay"/> instances,
/// one for each connected display.
/// </param>
internal static bool QueryDisplays(int fd, List <LinuxDisplay> displays)
{
unsafe
{
bool has_displays = false;
if (displays != null)
{
displays.Clear();
}
ModeRes *resources = (ModeRes *)Drm.ModeGetResources(fd);
if (resources == null)
{
Debug.Print("[KMS] Drm.ModeGetResources failed.");
return(false);
}
Debug.Print("[KMS] DRM found {0} connectors", resources->count_connectors);
// Search for a valid connector
ModeConnector *connector = null;
for (int i = 0; i < resources->count_connectors; i++)
{
connector = (ModeConnector *)Drm.ModeGetConnector(fd,
*(resources->connectors + i));
if (connector != null)
{
bool success = false;
LinuxDisplay display = null;
try
{
if (connector->connection == ModeConnection.Connected &&
connector->count_modes > 0)
{
success = QueryDisplay(fd, connector, out display);
has_displays |= success;
}
}
catch (Exception e)
{
Debug.Print("[KMS] Failed to add display. Error: {0}", e);
}
if (success && displays != null)
{
displays.Add(display);
}
else
{
Drm.ModeFreeConnector((IntPtr)connector);
connector = null;
}
}
}
return(has_displays);
}
}
