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path: root/drivers/gpu/drm/drm_edid.c
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Diffstat (limited to 'drivers/gpu/drm/drm_edid.c')
-rw-r--r--drivers/gpu/drm/drm_edid.c183
1 files changed, 155 insertions, 28 deletions
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index a839a28d8ee..c67400067b8 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -550,11 +550,20 @@ static int add_detailed_info(struct drm_connector *connector,
}
#define DDC_ADDR 0x50
-
-unsigned char *drm_do_probe_ddc_edid(struct i2c_adapter *adapter)
+/**
+ * Get EDID information via I2C.
+ *
+ * \param adapter : i2c device adaptor
+ * \param buf : EDID data buffer to be filled
+ * \param len : EDID data buffer length
+ * \return 0 on success or -1 on failure.
+ *
+ * Try to fetch EDID information by calling i2c driver function.
+ */
+int drm_do_probe_ddc_edid(struct i2c_adapter *adapter,
+ unsigned char *buf, int len)
{
unsigned char start = 0x0;
- unsigned char *buf = kmalloc(EDID_LENGTH, GFP_KERNEL);
struct i2c_msg msgs[] = {
{
.addr = DDC_ADDR,
@@ -564,31 +573,36 @@ unsigned char *drm_do_probe_ddc_edid(struct i2c_adapter *adapter)
}, {
.addr = DDC_ADDR,
.flags = I2C_M_RD,
- .len = EDID_LENGTH,
+ .len = len,
.buf = buf,
}
};
- if (!buf) {
- dev_warn(&adapter->dev, "unable to allocate memory for EDID "
- "block.\n");
- return NULL;
- }
-
if (i2c_transfer(adapter, msgs, 2) == 2)
- return buf;
+ return 0;
dev_info(&adapter->dev, "unable to read EDID block.\n");
- kfree(buf);
- return NULL;
+ return -1;
}
EXPORT_SYMBOL(drm_do_probe_ddc_edid);
-static unsigned char *drm_ddc_read(struct i2c_adapter *adapter)
+/**
+ * Get EDID information.
+ *
+ * \param adapter : i2c device adaptor.
+ * \param buf : EDID data buffer to be filled
+ * \param len : EDID data buffer length
+ * \return 0 on success or -1 on failure.
+ *
+ * Initialize DDC, then fetch EDID information
+ * by calling drm_do_probe_ddc_edid function.
+ */
+static int drm_ddc_read(struct i2c_adapter *adapter,
+ unsigned char *buf, int len)
{
struct i2c_algo_bit_data *algo_data = adapter->algo_data;
- unsigned char *edid = NULL;
int i, j;
+ int ret = -1;
algo_data->setscl(algo_data->data, 1);
@@ -616,7 +630,7 @@ static unsigned char *drm_ddc_read(struct i2c_adapter *adapter)
msleep(15);
/* Do the real work */
- edid = drm_do_probe_ddc_edid(adapter);
+ ret = drm_do_probe_ddc_edid(adapter, buf, len);
algo_data->setsda(algo_data->data, 0);
algo_data->setscl(algo_data->data, 0);
msleep(15);
@@ -632,7 +646,7 @@ static unsigned char *drm_ddc_read(struct i2c_adapter *adapter)
msleep(15);
algo_data->setscl(algo_data->data, 0);
algo_data->setsda(algo_data->data, 0);
- if (edid)
+ if (ret == 0)
break;
}
/* Release the DDC lines when done or the Apple Cinema HD display
@@ -641,9 +655,31 @@ static unsigned char *drm_ddc_read(struct i2c_adapter *adapter)
algo_data->setsda(algo_data->data, 1);
algo_data->setscl(algo_data->data, 1);
- return edid;
+ return ret;
}
+static int drm_ddc_read_edid(struct drm_connector *connector,
+ struct i2c_adapter *adapter,
+ char *buf, int len)
+{
+ int ret;
+
+ ret = drm_ddc_read(adapter, buf, len);
+ if (ret != 0) {
+ dev_info(&connector->dev->pdev->dev, "%s: no EDID data\n",
+ drm_get_connector_name(connector));
+ goto end;
+ }
+ if (!edid_is_valid((struct edid *)buf)) {
+ dev_warn(&connector->dev->pdev->dev, "%s: EDID invalid.\n",
+ drm_get_connector_name(connector));
+ ret = -1;
+ }
+end:
+ return ret;
+}
+
+#define MAX_EDID_EXT_NUM 4
/**
* drm_get_edid - get EDID data, if available
* @connector: connector we're probing
@@ -656,27 +692,118 @@ static unsigned char *drm_ddc_read(struct i2c_adapter *adapter)
struct edid *drm_get_edid(struct drm_connector *connector,
struct i2c_adapter *adapter)
{
+ int ret;
struct edid *edid;
- edid = (struct edid *)drm_ddc_read(adapter);
- if (!edid) {
- dev_info(&connector->dev->pdev->dev, "%s: no EDID data\n",
- drm_get_connector_name(connector));
- return NULL;
+ edid = kmalloc(EDID_LENGTH * (MAX_EDID_EXT_NUM + 1),
+ GFP_KERNEL);
+ if (edid == NULL) {
+ dev_warn(&connector->dev->pdev->dev,
+ "Failed to allocate EDID\n");
+ goto end;
}
- if (!edid_is_valid(edid)) {
- dev_warn(&connector->dev->pdev->dev, "%s: EDID invalid.\n",
- drm_get_connector_name(connector));
- kfree(edid);
- return NULL;
+
+ /* Read first EDID block */
+ ret = drm_ddc_read_edid(connector, adapter,
+ (unsigned char *)edid, EDID_LENGTH);
+ if (ret != 0)
+ goto clean_up;
+
+ /* There are EDID extensions to be read */
+ if (edid->extensions != 0) {
+ int edid_ext_num = edid->extensions;
+
+ if (edid_ext_num > MAX_EDID_EXT_NUM) {
+ dev_warn(&connector->dev->pdev->dev,
+ "The number of extension(%d) is "
+ "over max (%d), actually read number (%d)\n",
+ edid_ext_num, MAX_EDID_EXT_NUM,
+ MAX_EDID_EXT_NUM);
+ /* Reset EDID extension number to be read */
+ edid_ext_num = MAX_EDID_EXT_NUM;
+ }
+ /* Read EDID including extensions too */
+ ret = drm_ddc_read_edid(connector, adapter, (char *)edid,
+ EDID_LENGTH * (edid_ext_num + 1));
+ if (ret != 0)
+ goto clean_up;
+
}
connector->display_info.raw_edid = (char *)edid;
+ goto end;
+clean_up:
+ kfree(edid);
+ edid = NULL;
+end:
return edid;
+
}
EXPORT_SYMBOL(drm_get_edid);
+#define HDMI_IDENTIFIER 0x000C03
+#define VENDOR_BLOCK 0x03
+/**
+ * drm_detect_hdmi_monitor - detect whether monitor is hdmi.
+ * @edid: monitor EDID information
+ *
+ * Parse the CEA extension according to CEA-861-B.
+ * Return true if HDMI, false if not or unknown.
+ */
+bool drm_detect_hdmi_monitor(struct edid *edid)
+{
+ char *edid_ext = NULL;
+ int i, hdmi_id, edid_ext_num;
+ int start_offset, end_offset;
+ bool is_hdmi = false;
+
+ /* No EDID or EDID extensions */
+ if (edid == NULL || edid->extensions == 0)
+ goto end;
+
+ /* Chose real EDID extension number */
+ edid_ext_num = edid->extensions > MAX_EDID_EXT_NUM ?
+ MAX_EDID_EXT_NUM : edid->extensions;
+
+ /* Find CEA extension */
+ for (i = 0; i < edid_ext_num; i++) {
+ edid_ext = (char *)edid + EDID_LENGTH * (i + 1);
+ /* This block is CEA extension */
+ if (edid_ext[0] == 0x02)
+ break;
+ }
+
+ if (i == edid_ext_num)
+ goto end;
+
+ /* Data block offset in CEA extension block */
+ start_offset = 4;
+ end_offset = edid_ext[2];
+
+ /*
+ * Because HDMI identifier is in Vendor Specific Block,
+ * search it from all data blocks of CEA extension.
+ */
+ for (i = start_offset; i < end_offset;
+ /* Increased by data block len */
+ i += ((edid_ext[i] & 0x1f) + 1)) {
+ /* Find vendor specific block */
+ if ((edid_ext[i] >> 5) == VENDOR_BLOCK) {
+ hdmi_id = edid_ext[i + 1] | (edid_ext[i + 2] << 8) |
+ edid_ext[i + 3] << 16;
+ /* Find HDMI identifier */
+ if (hdmi_id == HDMI_IDENTIFIER)
+ is_hdmi = true;
+ break;
+ }
+ }
+
+end:
+ return is_hdmi;
+}
+EXPORT_SYMBOL(drm_detect_hdmi_monitor);
+
/**
* drm_add_edid_modes - add modes from EDID data, if available
* @connector: connector we're probing