[Intel-gfx] [PATCH] drm/i915: Add 30ms delay in course of SDVO-TV detection

[yakui.zhao at intel.com]

From: Zhao Yakui <yakui.zhao at intel.com>

Add 30ms delay in course of SDVO-TV detection. Otherwise sometimes the SDVO-TV
can't be detected correctly although it is connected.

https://bugs.freedesktop.org/show_bug.cgi?id=24290
https://bugs.freedesktop.org/show_bug.cgi?id=20785

Signed-off-by: Zhao Yakui <yakui.zhao at intel.com>
Tested-by: Yan Seiner <yan at seiner.com>
---
 drivers/gpu/drm/i915/intel_sdvo.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 55b8beb..dba5147 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -1617,6 +1617,10 @@ static enum drm_connector_status intel_sdvo_detect(struct drm_connector *connect
 
 	intel_sdvo_write_cmd(intel_output,
 			     SDVO_CMD_GET_ATTACHED_DISPLAYS, NULL, 0);
+	if (sdvo_priv->is_tv) {
+		/* add 30ms delay when the output type is SDVO-TV */
+		mdelay(30);
+	}
 	status = intel_sdvo_read_response(intel_output, &response, 2);
 
 	DRM_DEBUG_KMS("SDVO response %d %d\n", response & 0xff, response >> 8);
-- 
1.5.4.5