Attachment 144154 Details for Bug 110604 – Test file: read-dpcd.c

Test file: read-dpcd.c

read-dpcd.c (text/x-csrc), 1.24 KB, created by Jason on 2019-05-04 04:26:59 UTC

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Filename:

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Creator: Jason

Created: 2019-05-04 04:26:59 UTC

Size: 1.24 KB

patch

obsolete

>#include <errno.h>
>#include <fcntl.h>
>#include <stdio.h>
>#include <stdlib.h>
>#include <string.h>
>#include <sys/types.h>
>#include <unistd.h>
>
>#define REG_RC_CAP		0x4B0
>#define REG_VENDOR_ID		0x500
>
>static int
>aux_read (int fd, off_t offset, char *buf, size_t len)
>{
>	if (lseek(fd, offset, SEEK_SET) != offset) {
>		fprintf(stderr, "  failed to lseek(%d, %ld)\n",
>			fd, offset);
>		return -1;
>	}
>
>	if (read(fd, buf, len) != len) {
>		fprintf(stderr, "  failed to read(%d, %lu)\n",
>			fd, len);
>		return -1;
>	}
>
>	return 0;
>}
>
>int main(int argc, char* argv[])
>{
>	int fd;
>	char buf[4];
>
>	if (argc < 2) {
>		fprintf(stderr, "Usage: %s /dev/drm_dp_aux<N>\n", argv[0]);
>		return -1;
>	}
>
>	fd = open(argv[1], O_RDWR);
>	if (fd == -1) {
>		fprintf(stderr, "failed to open device %s: %s\n",
>			argv[0], strerror(errno));
>		return -1;
>	}
>
>	if (aux_read(fd, REG_RC_CAP, buf, 1) < 0) {
>		fprintf(stderr, "failed to get capability\n");
>		return -1;
>	}
>
>	printf("Capability: 0x%02x\n", buf[0]);
>	if (!(buf[0] & 0x04))
>		return -1;
>
>	if (aux_read(fd, REG_VENDOR_ID, buf, 3) < 0) {
>		fprintf(stderr, "failed to read vendor ID\n");
>		return -1;
>	}
>
>	printf("Vendor ID: %02x%02x%02x\n", buf[0], buf[1], buf[2]);
>	if (buf[0] == 0x90 && buf[1] == 0xCC && buf[2] == 0x24)
>		return 0;
>
>	return -1;
>}

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