drm: Add aspect ratio parsing in DRM layer

Current DRM layer functions don't parse aspect ratio information
while converting a user mode->kernel mode or vice versa. This
causes modeset to pick mode with wrong aspect ratio, eventually
causing failures in HDMI compliance test cases, due to wrong VIC.

This patch adds aspect ratio information in DRM's mode conversion
and mode comparision functions, to make sure kernel picks mode
with right aspect ratio (as per the VIC).

Background:
This patch was once reviewed and merged, and later reverted due to
lack of DRM cap protection. This is a re-spin of this patch, this
time with DRM cap protection, to avoid aspect ratio information, when
the client doesn't request for it.

Review link: https://pw-emeril.freedesktop.org/patch/104068/
Background discussion: https://patchwork.kernel.org/patch/9379057/

Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
Signed-off-by: Lin, Jia <lin.a.jia@intel.com>
Signed-off-by: Akashdeep Sharma <akashdeep.sharma@intel.com>
Reviewed-by: Jim Bride <jim.bride@linux.intel.com> (V2)
Reviewed-by: Jose Abreu <Jose.Abreu@synopsys.com> (V4)

Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: Jim Bride <jim.bride@linux.intel.com>
Cc: Jose Abreu <Jose.Abreu@synopsys.com>
Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com>

V3: modified the aspect-ratio check in drm_mode_equal as per new flags
    provided by Ville. https://patchwork.freedesktop.org/patch/188043/
V4: rebase
V5: rebase
V6: As recommended by Ville, avoided matching of aspect-ratio in
    drm_fb_helper, while trying to find a common mode among connectors
    for the target clone mode.
V7: rebase
V8: rebase
V9: rebase
V10: rebase
V11: rebase
V12: rebase
V13: rebase
V14: rebase

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1525777785-9740-10-git-send-email-ankit.k.nautiyal@intel.com

1 files changed, 34 insertions, 1 deletions

diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
index c395a244f665..7dfabdd6bcc8 100644
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -1049,7 +1049,8 @@ bool drm_mode_equal(const struct drm_display_mode *mode1,
 			      DRM_MODE_MATCH_TIMINGS |
 			      DRM_MODE_MATCH_CLOCK |
 			      DRM_MODE_MATCH_FLAGS |
-			      DRM_MODE_MATCH_3D_FLAGS);
+			      DRM_MODE_MATCH_3D_FLAGS|
+			      DRM_MODE_MATCH_ASPECT_RATIO);
 }
 EXPORT_SYMBOL(drm_mode_equal);
 
@@ -1647,6 +1648,20 @@ void drm_mode_convert_to_umode(struct drm_mode_modeinfo *out,
 	out->vrefresh = in->vrefresh;
 	out->flags = in->flags;
 	out->type = in->type;
+
+	switch (in->picture_aspect_ratio) {
+	case HDMI_PICTURE_ASPECT_4_3:
+		out->flags |= DRM_MODE_FLAG_PIC_AR_4_3;
+		break;
+	case HDMI_PICTURE_ASPECT_16_9:
+		out->flags |= DRM_MODE_FLAG_PIC_AR_16_9;
+		break;
+	case HDMI_PICTURE_ASPECT_RESERVED:
+	default:
+		out->flags |= DRM_MODE_FLAG_PIC_AR_NONE;
+		break;
+	}
+
 	strncpy(out->name, in->name, DRM_DISPLAY_MODE_LEN);
 	out->name[DRM_DISPLAY_MODE_LEN-1] = 0;
 }
@@ -1693,6 +1708,24 @@ int drm_mode_convert_umode(struct drm_device *dev,
 	strncpy(out->name, in->name, DRM_DISPLAY_MODE_LEN);
 	out->name[DRM_DISPLAY_MODE_LEN-1] = 0;
 
+	/* Clearing picture aspect ratio bits from out flags,
+	 * as the aspect-ratio information is not stored in
+	 * flags for kernel-mode, but in picture_aspect_ratio.
+	 */
+	out->flags &= ~DRM_MODE_FLAG_PIC_AR_MASK;
+
+	switch (in->flags & DRM_MODE_FLAG_PIC_AR_MASK) {
+	case DRM_MODE_FLAG_PIC_AR_4_3:
+		out->picture_aspect_ratio |= HDMI_PICTURE_ASPECT_4_3;
+		break;
+	case DRM_MODE_FLAG_PIC_AR_16_9:
+		out->picture_aspect_ratio |= HDMI_PICTURE_ASPECT_16_9;
+		break;
+	default:
+		out->picture_aspect_ratio = HDMI_PICTURE_ASPECT_NONE;
+		break;
+	}
+
 	out->status = drm_mode_validate_driver(dev, out);
 	if (out->status != MODE_OK)
 		return -EINVAL;