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path: root/drivers/gpu/drm/radeon/radeon_i2c.c
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Diffstat (limited to 'drivers/gpu/drm/radeon/radeon_i2c.c')
-rw-r--r--drivers/gpu/drm/radeon/radeon_i2c.c32
1 files changed, 24 insertions, 8 deletions
diff --git a/drivers/gpu/drm/radeon/radeon_i2c.c b/drivers/gpu/drm/radeon/radeon_i2c.c
index 781196db792..6c111c1fa3f 100644
--- 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 */