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Code Issues Releases Activity

Improve HDMI display detection by searching the CEA-861 extension block for

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an HDMI vendor-specific data block (VSDB) containing the HDMI 24-bit IEEE
registration ID (0x000C03).

Approved by:	gonzo (mentor)
This commit is contained in:
Jared McNeill 2016-04-02 16:53:12 +00:00
parent e881d8757c
commit bfba653b0e
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=297514
1 changed files with 48 additions and 1 deletions
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49
sys/arm/allwinner/a10_hdmi.c
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@ -195,6 +195,15 @@ __FBSDID("$FreeBSD$");
#define CEA_TAG_ID 0x02
#define CEA_DTD 0x03
#define DTD_BASIC_AUDIO (1 << 6)
#define CEA_REV 0x02
#define CEA_DATA_OFF 0x03
#define CEA_DATA_START 4
#define BLOCK_TAG(x) (((x) >> 5) & 0x7)
#define BLOCK_TAG_VSDB 3
#define BLOCK_LEN(x) ((x) & 0x1f)
#define HDMI_VSDB_MINLEN 5
#define HDMI_OUI "\x03\x0c\x00"
#define HDMI_OUI_LEN 3
struct a10hdmi_softc {
struct resource *res;
@ -372,6 +381,41 @@ a10hdmi_ddc_read(struct a10hdmi_softc *sc, int block, uint8_t *edid)
return (0);
}
static int
a10hdmi_detect_hdmi_vsdb(uint8_t *edid)
{
int off, p, btag, blen;
if (edid[EXT_TAG] != CEA_TAG_ID)
return (0);
off = edid[CEA_DATA_OFF];
/* CEA data block collection starts at byte 4 */
if (off <= CEA_DATA_START)
return (0);
/* Parse the CEA data blocks */
for (p = CEA_DATA_START; p < off;) {
btag = BLOCK_TAG(edid[p]);
blen = BLOCK_LEN(edid[p]);
/* Make sure the length is sane */
if (p + blen + 1 > off)
break;
/* Look for a VSDB with the HDMI 24-bit IEEE registration ID */
if (btag == BLOCK_TAG_VSDB && blen >= HDMI_VSDB_MINLEN &&
memcmp(&edid[p + 1], HDMI_OUI, HDMI_OUI_LEN) == 0)
return (1);
/* Next data block */
p += (1 + blen);
}
return (0);
}
static void
a10hdmi_detect_hdmi(struct a10hdmi_softc *sc, int *phdmi, int *paudio)
{
@ -389,7 +433,7 @@ a10hdmi_detect_hdmi(struct a10hdmi_softc *sc, int *phdmi, int *paudio)
if (a10hdmi_ddc_read(sc, block, edid) != 0)
return;
if (edid[EXT_TAG] == CEA_TAG_ID) {
if (a10hdmi_detect_hdmi_vsdb(edid) != 0) {
*phdmi = 1;
*paudio = ((edid[CEA_DTD] & DTD_BASIC_AUDIO) != 0);
return;
@ -518,6 +562,9 @@ a10hdmi_set_videomode(device_t dev, const struct videomode *mode)
PLLCTRL0_VCO_S);
/* Setup display settings */
if (bootverbose)
device_printf(dev, "HDMI: %s, Audio: %s\n",
sc->has_hdmi ? "yes" : "no", sc->has_audio ? "yes" : "no");
val = 0;
if (sc->has_hdmi)
val |= VID_CTRL_HDMI_MODE;