Re: H55 chipset and KMS with HDMI/VGA

[Chris Wilson <chris@chris-wilson.co.uk>]

On Wed, 6 Oct 2010 22:57:49 -0700, milk <niteshadez@gmail.com> wrote:
> I recently purchased a Shuttle SH55J2 which has the Intel H55 chipset
> (Auburndale). Using xf86-video-intel-2.12.0-3 for arch linux, I am
> having KMS issues with the VGA/HDMI output. With KMS enabled, the VGA
> output is wavey and unreadable and the HDMI output has either no
> signal on an HDMI monitor or wrong colors (pink or green background,
> white text) using a HDMI->DVI converter. With KMS disabled, VGA and
> HDMI are fine, but X cannot startup because it now requires KMS to be
> enabled.

Seems like you've been bitten by two separate bugs. The first is that we
always enable audio over HDMI even through a dongle and to a device that
is not audio capable. That has the effect of making the output green/pink
or even preventing sync'ing entirely. The second is that for some reason
we have not been able to get VGA 100% reliable on Ironlake, which is
itself very peculiar.

To fix the first:
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi
index 9fb9501..084a987 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -73,7 +73,7 @@ static void intel_hdmi_mode_set(struct drm_encoder *encoder,
                sdvox |= SDVO_HSYNC_ACTIVE_HIGH;
 
        if (intel_hdmi->has_hdmi_sink) {
-               sdvox |= SDVO_AUDIO_ENABLE;
+               //sdvox |= SDVO_AUDIO_ENABLE;
                if (HAS_PCH_CPT(dev))
                        sdvox |= HDMI_MODE_SELECT;
        }

and we hope to have a complete patch shortly. (Zhenyu did you get a chance
to update the patches?)

For the second issue with the wavering VGA, could you please attach your
Xorg.log and an intel_reg_dumper output to
https://bugs.freedesktop.org/show_bug.cgi?id=28306 (and obviously look
carefully at that bug to see if the video of the symptoms are indeed the
same.) An alternative explanation might be that is a self-refresh issue
instead.

Thanks,
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre