xfree86: Add a xf86MonitorFindHDMIBlock()

The HDMI CEA vendor specific block has some interesting information,
such as the maximum TMDS dot clock.

v2: Don't parse CEA blocks with invalid offsets, remove spurious
    brackets (Chris Wilson)

v3: Fix the looping through the CEA data blocks, it had a typo using the
    wrong variable coming from the code it was ported from.
    Replace x << 16 + y << 8 + z by x << 16 | y << 8 | z
    (Chris Wilson)

v4: Remove the stray ';' at the end of "if (*end == 0)".
    (Dominik Behr on IRC)

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
This commit is contained in:
Damien Lespiau 2013-07-31 19:11:45 +01:00
parent 2ea973e12f
commit a279fb3ff3
2 changed files with 93 additions and 0 deletions

View File

@ -332,6 +332,97 @@ xf86ForEachVideoBlock(xf86MonPtr mon, handle_video_fn fn, void *data)
}
}
static Bool
cea_db_offsets(Uchar *cea, int *start, int *end)
{
/* Data block offset in CEA extension block */
*start = CEA_EXT_MIN_DATA_OFFSET;
*end = cea[2];
if (*end == 0)
*end = CEA_EXT_MAX_DATA_OFFSET;
if (*end < CEA_EXT_MIN_DATA_OFFSET || *end > CEA_EXT_MAX_DATA_OFFSET)
return FALSE;
return TRUE;
}
static int
cea_db_len(Uchar *db)
{
return db[0] & 0x1f;
}
static int
cea_db_tag(Uchar *db)
{
return db[0] >> 5;
}
typedef void (*handle_cea_db_fn) (Uchar *, void *);
static void
cea_for_each_db(xf86MonPtr mon, handle_cea_db_fn fn, void *data)
{
int i;
if (!mon)
return;
if (!(mon->flags & EDID_COMPLETE_RAWDATA))
return;
if (!mon->no_sections)
return;
if (!mon->rawData)
return;
for (i = 0; i < mon->no_sections; i++) {
int start, end, offset;
Uchar *ext;
ext = mon->rawData + EDID1_LEN * (i + 1);
if (ext[EXT_TAG] != CEA_EXT)
continue;
if (!cea_db_offsets(ext, &start, &end))
continue;
for (offset = start;
offset < end && offset + cea_db_len(&ext[offset]) < end;
offset += cea_db_len(&ext[offset]) + 1)
fn(&ext[offset], data);
}
}
struct find_hdmi_block_data {
struct cea_data_block *hdmi;
};
static void find_hdmi_block(Uchar *db, void *data)
{
struct find_hdmi_block_data *result = data;
int oui;
if (cea_db_tag(db) != CEA_VENDOR_BLK)
return;
if (cea_db_len(db) < 5)
return;
oui = (db[3] << 16) | (db[2] << 8) | db[1];
if (oui == IEEE_ID_HDMI)
result->hdmi = (struct cea_data_block *)db;
}
struct cea_data_block *xf86MonitorFindHDMIBlock(xf86MonPtr mon)
{
struct find_hdmi_block_data result = { NULL };
cea_for_each_db(mon, find_hdmi_block, &result);
return result.hdmi;
}
xf86MonPtr
xf86InterpretEEDID(int scrnIndex, Uchar * block)
{

View File

@ -98,4 +98,6 @@ typedef void (*handle_video_fn) (struct cea_video_block *, void *);
void xf86ForEachVideoBlock(xf86MonPtr, handle_video_fn, void *);
struct cea_data_block *xf86MonitorFindHDMIBlock(xf86MonPtr mon);
#endif