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Diffstat (limited to 'xorg-server/hw/xfree86/ddc/edid.c')
-rw-r--r--xorg-server/hw/xfree86/ddc/edid.c140
1 files changed, 140 insertions, 0 deletions
diff --git a/xorg-server/hw/xfree86/ddc/edid.c b/xorg-server/hw/xfree86/ddc/edid.c
new file mode 100644
index 000000000..3ebafbbba
--- /dev/null
+++ b/xorg-server/hw/xfree86/ddc/edid.c
@@ -0,0 +1,140 @@
+
+/* edid.c: retrieve EDID record from raw DDC1 data stream: data
+ * is contained in an array of unsigned int each unsigned int
+ * contains one bit if bit is 0 unsigned int has to be zero else
+ * unsigned int > 0
+ *
+ * Copyright 1998 by Egbert Eich <Egbert.Eich@Physik.TU-Darmstadt.DE>
+ */
+#ifdef HAVE_XORG_CONFIG_H
+#include <xorg-config.h>
+#endif
+
+#include "misc.h"
+#include "xf86.h"
+#include "xf86_OSproc.h"
+#include "xf86DDC.h"
+#include "ddcPriv.h"
+#include <string.h>
+
+static int find_start(unsigned int *);
+static unsigned char * find_header(unsigned char *);
+static unsigned char * resort(unsigned char *);
+
+unsigned char *
+GetEDID_DDC1(unsigned int *s_ptr)
+{
+ unsigned char *d_block, *d_pos;
+ unsigned int *s_pos, *s_end;
+ int s_start;
+ int i,j;
+ s_start = find_start(s_ptr);
+ if (s_start==-1) return NULL;
+ s_end = s_ptr + NUM;
+ s_pos = s_ptr + s_start;
+ d_block=xalloc(EDID1_LEN);
+ if (!d_block) return NULL;
+ d_pos = d_block;
+ for (i=0;i<EDID1_LEN;i++) {
+ for (j=0;j<8;j++) {
+ *d_pos <<= 1;
+ if (*s_pos) {
+ *d_pos |= 0x01;
+ }
+ s_pos++; if (s_pos == s_end) s_pos=s_ptr;
+ };
+ s_pos++; if (s_pos == s_end) s_pos=s_ptr;
+ d_pos++;
+ }
+ xfree(s_ptr);
+ if (d_block && DDC_checksum(d_block,EDID1_LEN)) return NULL;
+ return (resort(d_block));
+}
+
+int
+DDC_checksum(unsigned char *block, int len)
+{
+ int i, result = 0;
+ int not_null = 0;
+
+ for (i=0;i<len;i++) {
+ not_null |= block[i];
+ result += block[i];
+ }
+
+#ifdef DEBUG
+ if (result & 0xFF) ErrorF("DDC checksum not correct\n");
+ if (!not_null) ErrorF("DDC read all Null\n");
+#endif
+
+ /* catch the trivial case where all bytes are 0 */
+ if (!not_null) return 1;
+
+ return (result&0xFF);
+}
+
+static int
+find_start(unsigned int *ptr)
+{
+ unsigned int comp[9], test[9];
+ int i,j;
+
+ for (i=0;i<9;i++){
+ comp[i] = *(ptr++);
+ test[i] = 1;
+ }
+ for (i=0;i<127;i++){
+ for (j=0;j<9;j++){
+ test[j] = test[j] & !(comp[j] ^ *(ptr++));
+ }
+ }
+ for (i=0;i<9;i++)
+ if (test[i]) return (i+1);
+ return (-1);
+}
+
+static unsigned char *
+find_header(unsigned char *block)
+{
+ unsigned char *ptr, *head_ptr, *end;
+ unsigned char header[]={0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00};
+
+ ptr = block;
+ end = block + EDID1_LEN;
+ while (ptr<end) {
+ int i;
+ head_ptr = ptr;
+ for (i=0;i<8;i++){
+ if (header[i] != *(head_ptr++)) break;
+ if (head_ptr == end) head_ptr = block;
+ }
+ if (i==8) break;
+ ptr++;
+ }
+ if (ptr == end) return (NULL);
+ return (ptr);
+}
+
+static unsigned char *
+resort(unsigned char *s_block)
+{
+ unsigned char *d_new, *d_ptr, *d_end, *s_ptr, *s_end;
+ unsigned char tmp;
+
+ s_end = s_block + EDID1_LEN;
+ d_new = xalloc(EDID1_LEN);
+ if (!d_new) return NULL;
+ d_end = d_new + EDID1_LEN;
+
+ s_ptr = find_header(s_block);
+ if (!s_ptr) return NULL;
+ for (d_ptr=d_new;d_ptr<d_end;d_ptr++){
+ tmp = *(s_ptr++);
+ *d_ptr = tmp;
+ if (s_ptr == s_end) s_ptr = s_block;
+ }
+ xfree(s_block);
+ return (d_new);
+}
+
+