On Tue, 2025-08-26 at 10:06 -0400, Alex Deucher wrote: > On Mon, Aug 25, 2025 at 5:33 PM Timur Kristóf > <timur.kris...@gmail.com> wrote: > > > > When the EDID has the HDMI bit, we should simply select > > the HDMI signal type even on DVI ports. > > > > For reference see, the legacy amdgpu display code: > > amdgpu_atombios_encoder_get_encoder_mode > > which selects ATOM_ENCODER_MODE_HDMI for the same case. > > > > This commit fixes DVI connectors to work with DVI-D/HDMI > > adapters so that they can now produce output over these > > connectors for HDMI monitors with higher bandwidth modes. > > With this change, even HDMI audio works through DVI. > > > > For testing, I used a CAA-DMDHFD3 DVI-D/HDMI adapter > > with the following GPUs: > > > > Tahiti (DCE 6) - DC can now output 4K 30 Hz over DVI > > Polaris 10 (DCE 11.2) - DC can now output 4K 60 Hz over DVI > > > > Signed-off-by: Timur Kristóf <timur.kris...@gmail.com> > > Makes sense to me, but would be good to get input from display team > in > case there is anything I'm missing. > Acked-by: Alex Deucher <alexander.deuc...@amd.com>
Thank you! I just want to add that the code path without audio for both DVI-D and HDMI seems to be broken and probably needs further investigation. I might come back to this problem later when/if I have an opportunity to test with a display that actually uses DVI-D. Right now I only have the DVI/HDMI adapter which seems to work differently (as noted in the above patch). Timur > > > --- > > drivers/gpu/drm/amd/display/dc/link/link_detection.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/gpu/drm/amd/display/dc/link/link_detection.c > > b/drivers/gpu/drm/amd/display/dc/link/link_detection.c > > index 827b630daf49..42180e6aca91 100644 > > --- a/drivers/gpu/drm/amd/display/dc/link/link_detection.c > > +++ b/drivers/gpu/drm/amd/display/dc/link/link_detection.c > > @@ -1140,6 +1140,10 @@ static bool > > detect_link_and_local_sink(struct dc_link *link, > > if (sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A && > > !sink->edid_caps.edid_hdmi) > > sink->sink_signal = > > SIGNAL_TYPE_DVI_SINGLE_LINK; > > + else if (dc_is_dvi_signal(sink->sink_signal) && > > + aud_support->hdmi_audio_native && > > + sink->edid_caps.edid_hdmi) > > + sink->sink_signal = > > SIGNAL_TYPE_HDMI_TYPE_A; > > > > if (link->local_sink && > > dc_is_dp_signal(sink_caps.signal)) > > dp_trace_init(link); > > -- > > 2.50.1 > >
