On Fri, Apr 22, 2016 at 10:58:34AM +0530, Sharma, Shashank wrote:

Thanks for the review Daniel.
My comments inline.

Regards
Shashank
On 4/21/2016 8:34 PM, Daniel Vetter wrote:

quoted

On Fri, Mar 25, 2016 at 01:47:35PM +0530, Shashank Sharma wrote:

quoted

HDMI 2.0/CEA-861-F introduces two new aspect ratios:
- 64:27
- 256:135

This patch adds support for these aspect ratios in
I915 driver, at various places.

Signed-off-by: Shashank Sharma <redacted>

Ok, we discussed this a bit internally and I had some questions. Reading
this series patches make sense up to this one, but here I have a few
questions/comments.

quoted

---
 drivers/gpu/drm/drm_modes.c       | 12 ++++++++++++
 drivers/gpu/drm/i915/intel_hdmi.c |  6 ++++++
 drivers/gpu/drm/i915/intel_sdvo.c |  6 ++++++
 3 files changed, 24 insertions(+)

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index 6e66136..11f219a 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c

@@ -1482,6 +1482,12 @@ void drm_mode_convert_to_umode(struct drm_mode_modeinfo *out,
 	case HDMI_PICTURE_ASPECT_16_9:
 		out->flags |= DRM_MODE_FLAG_PAR16_9;
 		break;
+	case HDMI_PICTURE_ASPECT_64_27:
+		out->flags |= DRM_MODE_FLAG_PAR64_27;
+		break;
+	case DRM_MODE_PICTURE_ASPECT_256_135:
+		out->flags |= DRM_MODE_FLAG_PAR256_135;
+		break;
 	case HDMI_PICTURE_ASPECT_NONE:
 	case HDMI_PICTURE_ASPECT_RESERVED:
 	default:

@@ -1544,6 +1550,12 @@ int drm_mode_convert_umode(struct drm_display_mode *out,
 	case DRM_MODE_FLAG_PAR16_9:
 		out->picture_aspect_ratio |= HDMI_PICTURE_ASPECT_16_9;
 		break;
+	case DRM_MODE_FLAG_PAR64_27:
+		out->picture_aspect_ratio |= HDMI_PICTURE_ASPECT_64_27;
+		break;
+	case DRM_MODE_FLAG_PAR256_135:
+		out->picture_aspect_ratio |= HDMI_PICTURE_ASPECT_256_135;
+		break;
 	default:
 		out->picture_aspect_ratio = HDMI_PICTURE_ASPECT_NONE;
 	}

Above two parts is core enabling, I guess those should be squashed into
the preceeding patch?

Sure, we can do this.
The idea was to create a separate patch for new aspect ratio, so that one
can segregate HDMI 2.0 patches and HDMI 1.4 patches. If you still recommend
this, I can move this part in next patch.

Definitely a good idea, and you have that separate patch already in "drm:
Add flags for new aspect ratios". I just think that the above 2 hunks
belong into the core patch, not the i915 enabling patch.

quoted

quoted

diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index e2dab48..bc8e2c8 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c

@@ -1545,6 +1545,12 @@ intel_hdmi_set_property(struct drm_connector *connector,
 		case DRM_MODE_PICTURE_ASPECT_16_9:
 			intel_hdmi->aspect_ratio = HDMI_PICTURE_ASPECT_16_9;
 			break;
+		case DRM_MODE_PICTURE_ASPECT_64_27:
+			intel_hdmi->aspect_ratio = HDMI_PICTURE_ASPECT_64_27;
+			break;
+		case DRM_MODE_PICTURE_ASPECT_256_135:
+			intel_hdmi->aspect_ratio = HDMI_PICTURE_ASPECT_256_135;
+			break;
 		default:
 			return -EINVAL;
 		}

diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index fae64bc..370e4f9 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c

@@ -2071,6 +2071,12 @@ intel_sdvo_set_property(struct drm_connector *connector,
 		case DRM_MODE_PICTURE_ASPECT_16_9:
 			intel_sdvo->aspect_ratio = HDMI_PICTURE_ASPECT_16_9;
 			break;
+		case DRM_MODE_PICTURE_ASPECT_64_27:
+			intel_sdvo->aspect_ratio = HDMI_PICTURE_ASPECT_64_27;
+			break;
+		case DRM_MODE_PICTURE_ASPECT_256_135:
+			intel_sdvo->aspect_ratio = HDMI_PICTURE_ASPECT_256_135;
+			break;
 		default:
 			return -EINVAL;
 		}

The trouble with the aspect_ratio prop as currently implemented is that we
currently unconditionally overwrite adjusted_mode->picture_aspect_ratio
with it.

But your patches here move the aspect ratio handling into
drm_mode_modeinfo (uabi) and drm_display_mode (kernel-internal), where it
imo belongs. But we need to figure out how to the interaction with the
property correctly. What's probably needed is a new value in the
aspect_ratio enum called "default", which selects the aspect_ratio from
the mode. Only when userspace overrides (NONE, or one of the CEA aspect
ratios) would we obey the aspect_ratio of the property. Otherwise the
aspect ratio stored in the mode would be lost.

This is exactly how we have handled this in Android branch(with NONE as
default), thanks for the suggestion. I will incorporate this in next patch
set.

Yeah, we can't reuse NONE in case someone wants to explicitly have no
aspect ratio (which means we'll not transmit the VIC code in the
infoframes most likely). At least I think adding a new DEFAULT instead of
overloading NONE is the better approach.

quoted

The other bit that I can't find in this series is making sure we compute
the VIC correctly for the new modes. Or does that magically work correctly
since we compare the full mode when selecting VICs?

Yes, we are saving the right VIC from EDID, so the VIC is now a part of the
mode flags, all we have to do extract this and write during preparing
AVI-IF, we have a small one line patch for that. I will add that too in the
next series.

Ah I was a bit unclear. But reading more code it's indeed that we have
aspect-ratio already stored in the edid parsing code for the VIC modes in
the static table. And with your kernel-mode to umode patches it'll show up
in the userspace mode list. And then userspace can request that mode, and
umode to kernel-mode will preserve it. And finally we can compute the
right VIC from that again.

So seems solid, only thing to change is how we take the i915 property into
account. On that topic: Do we really need to keep that property, or could
we just remove it? I assume the only real user is android, and that's
still closed, so we could just nuke it I guess ;-) That would be even
simpler.

And with the new flags userspace still has the option to override the
aspect ratio mode if it wants to.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch