4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Tomi Valkeinen <redacted>

commit b201e743f42d143f4bcdcb14587caf7cb1d99229 upstream.

When setting mode via MODE_ID property,
drm_atomic_set_mode_prop_for_crtc() does not call
drm_mode_set_crtcinfo() which possibly causes:

"[drm:drm_calc_timestamping_constants [drm]] *ERROR* crtc 32: Can't
calculate constants, dotclock = 0!"

Whether the error is seen depends on the previous data in state->mode,
as state->mode is not cleared when setting new mode.

This patch adds drm_mode_set_crtcinfo() call to
drm_mode_convert_umode(), which is called in both legacy and atomic
paths. This should be fine as there's no reason to call
drm_mode_convert_umode() without also setting the crtc related fields.

drm_mode_set_crtcinfo() is removed from the legacy drm_mode_setcrtc() as
that is no longer needed.

Signed-off-by: Tomi Valkeinen <redacted>
Reviewed-by: Daniel Vetter <redacted>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/drm_crtc.c  |    2 --
 drivers/gpu/drm/drm_modes.c |    2 ++
 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c

@@ -2682,8 +2682,6 @@ int drm_mode_setcrtc(struct drm_device *
 			goto out;
 		}
 
-		drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
-
 		/*
 		 * Check whether the primary plane supports the fb pixel format.
 		 * Drivers not implementing the universal planes API use a
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c

@@ -1487,6 +1487,8 @@ int drm_mode_convert_umode(struct drm_di
 	if (out->status != MODE_OK)
 		goto out;
 
+	drm_mode_set_crtcinfo(out, CRTC_INTERLACE_HALVE_V);
+
 	ret = 0;
 
 out: