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authorHans Verkuil <hans.verkuil@cisco.com>2018-08-27 09:58:17 +0200
committerHans Verkuil <hans.verkuil@cisco.com>2018-08-31 10:20:38 +0200
commit9bcf6d9868ae95fc7e5eda3dae5200f234ea5623 (patch)
tree0816f3162ccfc4be5acb688ba787de3bbeed8790 /drivers/gpu/drm/drm_dp_cec.c
parent5ce70c799ac22c142061c71aaeae518f04283472 (diff)
drm_dp_cec: add note about good MegaChips 2900 CEC support
A big problem with DP CEC-Tunneling-over-AUX is that it is tricky to find adapters with a chipset that supports this AND where the manufacturer actually connected the HDMI CEC line to the chipset. Add a mention of the MegaChips 2900 chipset which seems to support this feature well. Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Acked-by: Alex Deucher <alexander.deucher@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180827075820.41109-3-hverkuil@xs4all.nl
Diffstat (limited to 'drivers/gpu/drm/drm_dp_cec.c')
-rw-r--r--drivers/gpu/drm/drm_dp_cec.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/gpu/drm/drm_dp_cec.c b/drivers/gpu/drm/drm_dp_cec.c
index 1407b13a8d5d..8a718f85079a 100644
--- a/drivers/gpu/drm/drm_dp_cec.c
+++ b/drivers/gpu/drm/drm_dp_cec.c
@@ -16,7 +16,9 @@
* here. Quite a few active (mini-)DP-to-HDMI or USB-C-to-HDMI adapters
* have a converter chip that supports CEC-Tunneling-over-AUX (usually the
* Parade PS176), but they do not wire up the CEC pin, thus making CEC
- * useless.
+ * useless. Note that MegaChips 2900-based adapters appear to have good
+ * support for CEC tunneling. Those adapters that I have tested using
+ * this chipset all have the CEC line connected.
*
* Sadly there is no way for this driver to know this. What happens is
* that a /dev/cecX device is created that is isolated and unable to see