video/hdmi: Don't let the user of this API create invalid infoframes

To set the active aspect ratio value in the AVI infoframe today, you not
only have to set the active_aspect field, but also the active_info_valid
bit. Out of the 1 user of this API, we had 100% misuse, forgetting the
_valid bit. This was fixed in:

  Author: Damien Lespiau <damien.lespiau@intel.com>
  Date:   Tue Aug 6 20:32:17 2013 +0100

      drm: Don't generate invalid AVI infoframes for CEA modes

We can do better and derive the _valid bit from the user wanting to set
the active aspect ratio.

v2: Fix multi-lines comment style (Thierry Reding)

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Dave Airlie <airlied@gmail.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/video/hdmi.c b/drivers/video/hdmi.c
index 635d5690dd5a..7ccc118fefed 100644
--- a/drivers/video/hdmi.c
+++ b/drivers/video/hdmi.c
@@ -96,7 +96,11 @@ ssize_t hdmi_avi_infoframe_pack(struct hdmi_avi_infoframe *frame, void *buffer,
 
         ptr[0] = ((frame->colorspace & 0x3) << 5) | (frame->scan_mode & 0x3);
 
-        if (frame->active_info_valid)
+        /*
+         * Data byte 1, bit 4 has to be set if we provide the active format
+         * aspect ratio
+         */
+        if (frame->active_aspect & 0xf)
                 ptr[0] |= BIT(4);
 
         if (frame->horizontal_bar_valid)