[Bug 101302] [HSW] no Intel HDMI video output with kernel 4.4 and 4.9

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=101302

--- Comment #16 from Jani Nikula <jani.nikula at intel.com> ---
(In reply to Jani Nikula from comment #10)
> +	type = DRM_DP_DUAL_MODE_TYPE1_DVI;

That really was a shot in the dark, and shouldn't really have made a
difference... but I guess it works by forcing 165 MHz max clock, and therefore
8 bpc instead of 12 bpc. That's all I can think of. 12 bpc leads to 222.75 MHz
clock which is pretty close to the 225 MHz limit.

So throw the old debug patch away, and try instead:

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c
b/drivers/gpu/drm/i915/intel_hdmi.c
index e6f8f30ce7bd..5c99189e9ccf 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -1463,7 +1463,9 @@ bool intel_hdmi_compute_config(struct intel_encoder
*encoder,

                /* Need to adjust the port link by 1.5x for 12bpc. */
                pipe_config->port_clock = clock_12bpc;
-       } else {
+       }
+
+       if (true) {
                DRM_DEBUG_KMS("picking bpc to 8 for HDMI output\n");
                desired_bpp = 8*3;


or alternatively set the "audio" property to "force-dvi" on the connector.

Please attach dmesg on the try.

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