[PATCH 3/3] Parse the EDID when outputs are added
Richard Hughes
hughsient at gmail.com
Fri Apr 19 08:02:12 PDT 2013
At the moment we're only extracting interesting strings. We have to be quite
careful parsing the EDID data, as vendors like to do insane things.
The original EDID parsing code was written by me for gnome-color-manager.
---
src/compositor-drm.c | 166 ++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 165 insertions(+), 1 deletion(-)
diff --git a/src/compositor-drm.c b/src/compositor-drm.c
index a454676..4f37447 100644
--- a/src/compositor-drm.c
+++ b/src/compositor-drm.c
@@ -25,6 +25,7 @@
#include <errno.h>
#include <stdlib.h>
+#include <ctype.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
@@ -131,6 +132,14 @@ struct drm_fb {
void *map;
};
+struct drm_edid {
+ char *monitor_name;
+ char *serial_number;
+ char *eisa_id;
+ char *pnp_id;
+ /* other things can be added as required */
+};
+
struct drm_output {
struct weston_output base;
@@ -140,6 +149,7 @@ struct drm_output {
uint32_t connector_id;
drmModeCrtcPtr original_crtc;
drmModePropertyBlobPtr edid_blob;
+ struct drm_edid *edid;
int vblank_pending;
int page_flip_pending;
@@ -1005,6 +1015,16 @@ static void
drm_output_fini_pixman(struct drm_output *output);
static void
+drm_edid_destroy(struct drm_edid *edid)
+{
+ free(edid->monitor_name);
+ free(edid->serial_number);
+ free(edid->eisa_id);
+ free(edid->pnp_id);
+ free(edid);
+}
+
+static void
drm_output_destroy(struct weston_output *output_base)
{
struct drm_output *output = (struct drm_output *) output_base;
@@ -1014,6 +1034,8 @@ drm_output_destroy(struct weston_output *output_base)
if (output->edid_blob)
drmModeFreePropertyBlob(output->edid_blob);
+ if (output->edid)
+ drm_edid_destroy (output->edid);
if (output->backlight)
backlight_destroy(output->backlight);
@@ -1490,6 +1512,131 @@ drm_output_fini_pixman(struct drm_output *output)
}
}
+static char *
+edid_parse_string (const uint8_t *data)
+{
+ char *text;
+ int i;
+ int replaced = 0;
+
+ /* this is always 12 bytes, but we can't guarantee it's null
+ * terminated or not junk. */
+ text = strndup ((const char *) data, 12);
+
+ /* remove insane chars */
+ for (i = 0; text[i] != '\0'; i++) {
+ if (text[i] == '\n' ||
+ text[i] == '\r')
+ text[i] = '\0';
+ }
+
+ /* nothing left? */
+ if (text[0] == '\0') {
+ free (text);
+ text = NULL;
+ goto out;
+ }
+
+ /* ensure string is printable */
+ for (i = 0; text[i] != '\0'; i++) {
+ if (!isprint (text[i])) {
+ text[i] = '-';
+ replaced++;
+ }
+ }
+
+ /* if the string is random junk, ignore the string */
+ if (replaced > 4) {
+ free (text);
+ text = NULL;
+ goto out;
+ }
+out:
+ return text;
+}
+
+#define EDID_DESCRIPTOR_ALPHANUMERIC_DATA_STRING 0xfe
+#define EDID_DESCRIPTOR_DISPLAY_PRODUCT_NAME 0xfc
+#define EDID_DESCRIPTOR_DISPLAY_PRODUCT_SERIAL_NUMBER 0xff
+#define EDID_OFFSET_DATA_BLOCKS 0x36
+#define EDID_OFFSET_LAST_BLOCK 0x6c
+#define EDID_OFFSET_PNPID 0x08
+#define EDID_OFFSET_SERIAL 0x0c
+
+static int
+edid_parse (struct drm_edid *edid, const uint8_t *data, size_t length)
+{
+ char *tmp;
+ int i;
+ int rc = 0;
+ uint32_t serial;
+
+ /* check header */
+ if (length < 128) {
+ rc = -1;
+ goto out;
+ }
+ if (data[0] != 0x00 || data[1] != 0xff) {
+ rc = -1;
+ goto out;
+ }
+
+ /* decode the PNP ID from three 5 bit words packed into 2 bytes
+ * /--08--\/--09--\
+ * 7654321076543210
+ * |\---/\---/\---/
+ * R C1 C2 C3 */
+ edid->pnp_id = malloc(4);
+ edid->pnp_id[0] = 'A' + ((data[EDID_OFFSET_PNPID+0] & 0x7c) / 4) - 1;
+ edid->pnp_id[1] = 'A' + ((data[EDID_OFFSET_PNPID+0] & 0x3) * 8) + ((data[EDID_OFFSET_PNPID+1] & 0xe0) / 32) - 1;
+ edid->pnp_id[2] = 'A' + (data[EDID_OFFSET_PNPID+1] & 0x1f) - 1;
+ edid->pnp_id[3] = '\0';;
+
+ /* maybe there isn't a ASCII serial number descriptor, so use this instead */
+ serial = (int32_t) data[EDID_OFFSET_SERIAL+0];
+ serial += (int32_t) data[EDID_OFFSET_SERIAL+1] * 0x100;
+ serial += (int32_t) data[EDID_OFFSET_SERIAL+2] * 0x10000;
+ serial += (int32_t) data[EDID_OFFSET_SERIAL+3] * 0x1000000;
+ if (serial > 0) {
+ edid->serial_number = malloc(9);
+ sprintf (edid->serial_number, "%li", (long int) serial);
+ }
+
+ /* parse EDID data */
+ for (i = EDID_OFFSET_DATA_BLOCKS;
+ i <= EDID_OFFSET_LAST_BLOCK;
+ i += 18) {
+ /* ignore pixel clock data */
+ if (data[i] != 0)
+ continue;
+ if (data[i+2] != 0)
+ continue;
+
+ /* any useful blocks? */
+ if (data[i+3] == EDID_DESCRIPTOR_DISPLAY_PRODUCT_NAME) {
+ tmp = edid_parse_string (&data[i+5]);
+ if (tmp != NULL) {
+ free (edid->monitor_name);
+ edid->monitor_name = tmp;
+ }
+ } else if (data[i+3] == EDID_DESCRIPTOR_DISPLAY_PRODUCT_SERIAL_NUMBER) {
+ tmp = edid_parse_string (&data[i+5]);
+ if (tmp != NULL) {
+ free (edid->serial_number);
+ edid->serial_number = tmp;
+ }
+ } else if (data[i+3] == EDID_DESCRIPTOR_ALPHANUMERIC_DATA_STRING) {
+ tmp = edid_parse_string (&data[i+5]);
+ if (tmp != NULL) {
+ free (edid->eisa_id);
+ edid->eisa_id = tmp;
+ }
+ }
+ }
+out:
+ return rc;
+}
+
static int
create_output_for_connector(struct drm_compositor *ec,
drmModeRes *resources,
@@ -1505,6 +1652,7 @@ create_output_for_connector(struct drm_compositor *ec,
drmModeCrtc *crtc;
drmModePropertyPtr property;
int i;
+ int rc;
char name[32];
const char *type_name;
@@ -1666,7 +1814,23 @@ create_output_for_connector(struct drm_compositor *ec,
weston_log("Got EDID blob %p of size %u.\n",
output->edid_blob->data,
output->edid_blob->length);
- /* FIXME: actually parse EDID */
+ output->edid = malloc(sizeof(struct drm_edid));
+ memset(output->edid, 0, sizeof *output->edid);
+ rc = edid_parse(output->edid,
+ output->edid_blob->data,
+ output->edid_blob->length);
+ if (!rc) {
+ weston_log("EDID data '%s', '%s', '%s'\n",
+ output->edid->pnp_id,
+ output->edid->monitor_name,
+ output->edid->serial_number);
+ if (output->edid->pnp_id)
+ output->base.make = output->edid->pnp_id;
+ if (output->edid->monitor_name)
+ output->base.model = output->edid->monitor_name;
+ if (output->edid->serial_number)
+ output->base.serial = output->edid->serial_number;
+ }
}
output->base.origin = output->base.current;
--
1.8.2
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