[igt-dev] [PATCH i-g-t v4 3/9] lib/igt_edid: add support for Vendor Specific Data blocks

Simon Ser
2019-05-15T07:29:35Z

For some reason HDMI audio won't work unless you cast a magic IEEE Registration
Identifier alongside with its appropriate Components of Source Physical
Address. The easiest way to do this is to capture a wild HDMI EDID, study it,
and blindly copy bytes because you don't understand anything about their
possible meaning (if any).

This commit also changes the SAD API exposed by igt_edid, to allow for both a
SAD block and a VSD block to be included in the same CEA block.

Signed-off-by: Simon Ser <simon.ser@intel.com>
Reviewed-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
---
lib/igt_edid.c | 72 +++++++++++++++++++++++++++++++++++++++-----------
lib/igt_edid.h | 23 ++++++++++++++--
2 files changed, 78 insertions(+), 17 deletions(-)

diff --git a/lib/igt_edid.c b/lib/igt_edid.c
index d01defb0925e..fbdb0c06b8d7 100644
--- a/lib/igt_edid.c
+++ b/lib/igt_edid.c
@@ -292,30 +292,72 @@ void cea_sad_init_pcm(struct cea_sad *sad, int channels,
}

/**
- * edid_ext_set_cea_sad: set an extension block to be CEA SAD
+ * cea_vsd_get_hdmi_default:
+ *
+ * Returns the default Vendor Specific Data block for HDMI.
*/
-void edid_ext_set_cea_sad(struct edid_ext *ext, const struct cea_sad *sads,
- size_t sads_len)
+const struct cea_vsd *cea_vsd_get_hdmi_default(size_t *size)
{
- struct edid_cea *cea = &ext->data.cea;
- struct edid_cea_data_block *data_block;
- size_t sads_size, data_block_size;
+ static char raw[sizeof(struct cea_vsd) + 4] = {0};
+ struct cea_vsd *vsd;
+
+ *size = sizeof(raw);
+
+ /* Magic incantation. Works better if you orient your screen in the
+ * direction of the VESA headquarters. */
+ vsd = (struct cea_vsd *) raw;
+ vsd->ieee_oui[0] = 0x03;
+ vsd->ieee_oui[1] = 0x0C;
+ vsd->ieee_oui[2] = 0x00;
+ vsd->data[0] = 0x10;
+ vsd->data[1] = 0x00;
+ vsd->data[2] = 0x38;
+ vsd->data[3] = 0x2D;
+
+ return vsd;
+}
+
+static void edid_cea_data_block_init(struct edid_cea_data_block *block,
+ enum edid_cea_data_type type, size_t size)
+{
+ assert(size <= 0xFF);
+ block->type_len = type << 5 | size;
+}

- memset(ext, 0, sizeof(struct edid_ext));
+size_t edid_cea_data_block_set_sad(struct edid_cea_data_block *block,
+ const struct cea_sad *sads, size_t sads_len)
+{
+ size_t sads_size;

sads_size = sizeof(struct cea_sad) * sads_len;
- data_block_size = sizeof(struct edid_cea_data_block) + sads_size;
+ edid_cea_data_block_init(block, EDID_CEA_DATA_AUDIO, sads_size);
+
+ memcpy(block->data.sads, sads, sads_size);
+
+ return sizeof(struct edid_cea_data_block) + sads_size;
+}
+
+size_t edid_cea_data_block_set_vsd(struct edid_cea_data_block *block,
+ const struct cea_vsd *vsd, size_t vsd_size)
+{
+ edid_cea_data_block_init(block, EDID_CEA_DATA_VENDOR_SPECIFIC,
+ vsd_size);
+
+ memcpy(block->data.vsds, vsd, vsd_size);
+
+ return sizeof(struct edid_cea_data_block) + vsd_size;
+}
+
+void edid_ext_set_cea(struct edid_ext *ext, size_t data_blocks_size,
+ uint8_t flags)
+{
+ struct edid_cea *cea = &ext->data.cea;

ext->tag = EDID_EXT_CEA;

cea->revision = 3;
- cea->dtd_start = 4 + data_block_size;
- cea->misc = 1 << 6; /* basic audio, no DTD */
-
- assert(sads_size <= 0xFF);
- data_block = (struct edid_cea_data_block *) cea->data;
- data_block->type_len = EDID_CEA_DATA_AUDIO << 5 | sads_size;
- memcpy(data_block->data.sads, sads, sads_size);
+ cea->dtd_start = 4 + data_blocks_size;
+ cea->misc = flags; /* just flags, no DTD */
}

void edid_ext_update_cea_checksum(struct edid_ext *ext)
diff --git a/lib/igt_edid.h b/lib/igt_edid.h
index 3668d733f06a..7edd7e38f41e 100644
--- a/lib/igt_edid.h
+++ b/lib/igt_edid.h
@@ -189,6 +189,12 @@ struct cea_sad {
uint8_t bitrate;
} __attribute__((packed));

+/* Vendor Specific Data */
+struct cea_vsd {
+ uint8_t ieee_oui[3];
+ char data[];
+};
+
enum edid_cea_data_type {
EDID_CEA_DATA_AUDIO = 1,
EDID_CEA_DATA_VIDEO = 2,
@@ -200,9 +206,17 @@ struct edid_cea_data_block {
uint8_t type_len; /* type is from enum edid_cea_data_type */
union {
struct cea_sad sads[0];
+ struct cea_vsd vsds[0];
} data;
} __attribute__((packed));

+enum edid_cea_flag {
+ EDID_CEA_YCBCR422 = 1 << 4,
+ EDID_CEA_YCBCR444 = 1 << 5,
+ EDID_CEA_BASIC_AUDIO = 1 << 6,
+ EDID_CEA_UNDERSCAN = 1 << 7,
+};
+
struct edid_cea {
uint8_t revision;
uint8_t dtd_start;
@@ -275,8 +289,13 @@ void detailed_timing_set_string(struct detailed_timing *dt,

void cea_sad_init_pcm(struct cea_sad *sad, int channels,
uint8_t sampling_rates, uint8_t sample_sizes);
-void edid_ext_set_cea_sad(struct edid_ext *ext, const struct cea_sad *sads,
- size_t sads_len);
void edid_ext_update_cea_checksum(struct edid_ext *ext);
+const struct cea_vsd *cea_vsd_get_hdmi_default(size_t *size);
+size_t edid_cea_data_block_set_sad(struct edid_cea_data_block *block,
+ const struct cea_sad *sads, size_t sads_len);
+size_t edid_cea_data_block_set_vsd(struct edid_cea_data_block *block,
+ const struct cea_vsd *vsd, size_t vsd_size);
+void edid_ext_set_cea(struct edid_ext *ext, size_t data_blocks_size,
+ uint8_t flags);

#endif