1 files changed, 93 insertions, 28 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index a839a28d8ee6..fab2bdf9c423 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
@@ -656,24 +692,53 @@ 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);