| Message ID | 20180817141122.9541-3-hverkuil@xs4all.nl (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/nouveau+amdgpu: add DP CEC-Tunneling-over-AUX (repost) | expand |
Reviewed-by: Lyude Paul <lyude@redhat.com> On Fri, 2018-08-17 at 16:11 +0200, Hans Verkuil wrote: > From: Hans Verkuil <hans.verkuil@cisco.com> > > 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> > --- > drivers/gpu/drm/drm_dp_cec.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > 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
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