pingxelflut/drm_example.c

#include <stdio.h>
#include <stdint.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/ioctl.h>
#include <drm/drm.h>
#include <drm/drm_mode.h>

int main()
{
//------------------------------------------------------------------------------
//Opening the DRI device
//------------------------------------------------------------------------------

	int dri_fd  = open("/dev/dri/card0",O_RDWR | O_CLOEXEC);

//------------------------------------------------------------------------------
//Kernel Mode Setting (KMS)
//------------------------------------------------------------------------------

	uint64_t res_fb_buf[10]={0},
			res_crtc_buf[10]={0},
			res_conn_buf[10]={0},
			res_enc_buf[10]={0};

	struct drm_mode_card_res res={0};

	//Become the "master" of the DRI device
	ioctl(dri_fd, DRM_IOCTL_SET_MASTER, 0);

	//Get resource counts
	ioctl(dri_fd, DRM_IOCTL_MODE_GETRESOURCES, &res);
	res.fb_id_ptr=(uint64_t)res_fb_buf;
	res.crtc_id_ptr=(uint64_t)res_crtc_buf;
	res.connector_id_ptr=(uint64_t)res_conn_buf;
	res.encoder_id_ptr=(uint64_t)res_enc_buf;
	//Get resource IDs
	ioctl(dri_fd, DRM_IOCTL_MODE_GETRESOURCES, &res);

	printf("fb: %d, crtc: %d, conn: %d, enc: %d\n",res.count_fbs,res.count_crtcs,res.count_connectors,res.count_encoders);

	void *fb_base[10];
	long fb_w[10];
	long fb_h[10];

	//Loop though all available connectors
	int i;
	for (i=0;i<res.count_connectors;i++)
	{
		struct drm_mode_modeinfo conn_mode_buf[20]={0};
		uint64_t	conn_prop_buf[20]={0},
					conn_propval_buf[20]={0},
					conn_enc_buf[20]={0};

		struct drm_mode_get_connector conn={0};

		conn.connector_id=res_conn_buf[i];

		ioctl(dri_fd, DRM_IOCTL_MODE_GETCONNECTOR, &conn);	//get connector resource counts
		conn.modes_ptr=(uint64_t)conn_mode_buf;
		conn.props_ptr=(uint64_t)conn_prop_buf;
		conn.prop_values_ptr=(uint64_t)conn_propval_buf;
		conn.encoders_ptr=(uint64_t)conn_enc_buf;
		ioctl(dri_fd, DRM_IOCTL_MODE_GETCONNECTOR, &conn);	//get connector resources

		//Check if the connector is OK to use (connected to something)
		if (conn.count_encoders<1 || conn.count_modes<1 || !conn.encoder_id || !conn.connection)
		{
			printf("Not connected\n");
			continue;
		}

//------------------------------------------------------------------------------
//Creating a dumb buffer
//------------------------------------------------------------------------------
		struct drm_mode_create_dumb create_dumb={0};
		struct drm_mode_map_dumb map_dumb={0};
		struct drm_mode_fb_cmd cmd_dumb={0};

		//If we create the buffer later, we can get the size of the screen first.
		//This must be a valid mode, so it's probably best to do this after we find
		//a valid crtc with modes.
		create_dumb.width = conn_mode_buf[0].hdisplay;
		create_dumb.height = conn_mode_buf[0].vdisplay;
		create_dumb.bpp = 32;
		create_dumb.flags = 0;
		create_dumb.pitch = 0;
		create_dumb.size = 0;
		create_dumb.handle = 0;
		ioctl(dri_fd, DRM_IOCTL_MODE_CREATE_DUMB, &create_dumb);

		cmd_dumb.width=create_dumb.width;
		cmd_dumb.height=create_dumb.height;
		cmd_dumb.bpp=create_dumb.bpp;
		cmd_dumb.pitch=create_dumb.pitch;
		cmd_dumb.depth=24;
		cmd_dumb.handle=create_dumb.handle;
		ioctl(dri_fd,DRM_IOCTL_MODE_ADDFB,&cmd_dumb);

		map_dumb.handle=create_dumb.handle;
		ioctl(dri_fd,DRM_IOCTL_MODE_MAP_DUMB,&map_dumb);

		fb_base[i] = mmap(0, create_dumb.size, PROT_READ | PROT_WRITE, MAP_SHARED, dri_fd, map_dumb.offset);
		fb_w[i]=create_dumb.width;
		fb_h[i]=create_dumb.height;

//------------------------------------------------------------------------------
//Kernel Mode Setting (KMS)
//------------------------------------------------------------------------------

		printf("%d : mode: %d, prop: %d, enc: %d\n",conn.connection,conn.count_modes,conn.count_props,conn.count_encoders);
		printf("modes: %dx%d FB: %d\n",conn_mode_buf[0].hdisplay,conn_mode_buf[0].vdisplay,fb_base[i]);

		struct drm_mode_get_encoder enc={0};

		enc.encoder_id=conn.encoder_id;
		ioctl(dri_fd, DRM_IOCTL_MODE_GETENCODER, &enc);	//get encoder

		struct drm_mode_crtc crtc={0};

		crtc.crtc_id=enc.crtc_id;
		ioctl(dri_fd, DRM_IOCTL_MODE_GETCRTC, &crtc);

		crtc.fb_id=cmd_dumb.fb_id;
		crtc.set_connectors_ptr=(uint64_t)&res_conn_buf[i];
		crtc.count_connectors=1;
		crtc.mode=conn_mode_buf[0];
		crtc.mode_valid=1;
		ioctl(dri_fd, DRM_IOCTL_MODE_SETCRTC, &crtc);
	}

	//Stop being the "master" of the DRI device
	ioctl(dri_fd, DRM_IOCTL_DROP_MASTER, 0);

	int x,y;
	for (i=0;i<100;i++)
	{
		int j;
		for (j=0;j<res.count_connectors;j++)
		{
			int col=(rand()%0x00ffffff)&0x00ff00ff;
			for (y=0;y<fb_h[j];y++)
				for (x=0;x<fb_w[j];x++)
				{
					int location=y*(fb_w[j]) + x;
					*(((uint32_t*)fb_base[j])+location)=col;
				}
		}
		usleep(100000);
	}

	return 0;
}