drm/i915: enable dip before writing data on gen4

While testing with the intel_infoframes tool on gen4, I see that when
video DIP is disabled, what we write to the DATA memory is not exactly
what we read back later.

This regression has been introduce in

commit 64a8fc0145a1d0fdc25fc9367c2e6c621955fb3b
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Thu Sep 22 11:16:00 2011 +0530

    drm/i915: fix ILK+ infoframe support

That commit was setting VIDEO_DIP_CTL to 0 when initializing, which
caused the problem.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=43947
Cc: stable@kernel.org
Tested-by: Yang Guang <guang.a.yang@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
[danvet: Pimped commit message by using the usual commit citation
layout.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index cae3e5f17a49d8b767a371710935dcf89146121a..2d7f47b56b6ae7a7b1922a328ab971fe9d63077a 100644 (file)
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -136,7 +136,7 @@ static void i9xx_write_infoframe(struct drm_encoder *encoder,
 
        val &= ~VIDEO_DIP_SELECT_MASK;
 
-       I915_WRITE(VIDEO_DIP_CTL, val | port | flags);
+       I915_WRITE(VIDEO_DIP_CTL, VIDEO_DIP_ENABLE | val | port | flags);
 
        for (i = 0; i < len; i += 4) {
                I915_WRITE(VIDEO_DIP_DATA, *data);