Merge branch 'slab/urgent' into slab/next

[pandora-kernel.git] / drivers / gpu / drm / radeon / radeon_i2c.c

diff --git a/drivers/gpu/drm/radeon/radeon_i2c.c b/drivers/gpu/drm/radeon/radeon_i2c.c
index 781196d..6c111c1 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_i2c.c
+++ b/drivers/gpu/drm/radeon/radeon_i2c.c
@@ -32,17 +32,17 @@
  * radeon_ddc_probe
  *
  */
-bool radeon_ddc_probe(struct radeon_connector *radeon_connector)
+bool radeon_ddc_probe(struct radeon_connector *radeon_connector, bool requires_extended_probe)
 {
-       u8 out_buf[] = { 0x0, 0x0};
-       u8 buf[2];
+       u8 out = 0x0;
+       u8 buf[8];
        int ret;
        struct i2c_msg msgs[] = {
                {
                        .addr = 0x50,
                        .flags = 0,
                        .len = 1,
-                       .buf = out_buf,
+                       .buf = &out,
                },
                {
                        .addr = 0x50,
@@ -52,15 +52,31 @@ bool radeon_ddc_probe(struct radeon_connector *radeon_connector)
                }
        };
 
+       /* Read 8 bytes from i2c for extended probe of EDID header */
+       if (requires_extended_probe)
+               msgs[1].len = 8;
+
        /* on hw with routers, select right port */
        if (radeon_connector->router.ddc_valid)
                radeon_router_select_ddc_port(radeon_connector);
 
        ret = i2c_transfer(&radeon_connector->ddc_bus->adapter, msgs, 2);
-       if (ret == 2)
-               return true;
-
-       return false;
+       if (ret != 2)
+               /* Couldn't find an accessible DDC on this connector */
+               return false;
+       if (requires_extended_probe) {
+               /* Probe also for valid EDID header
+                * EDID header starts with:
+                * 0x00,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0x00.
+                * Only the first 6 bytes must be valid as
+                * drm_edid_block_valid() can fix the last 2 bytes */
+               if (drm_edid_header_is_valid(buf) < 6) {
+                       /* Couldn't find an accessible EDID on this
+                        * connector */
+                       return false;
+               }
+       }
+       return true;
 }
 
 /* bit banging i2c */