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SubjectRe: [PATCH v2] drm/amd/display: Reduce HDMI pixel encoding if max clock is exceeded
On Thu, Jan 2, 2020 at 10:14 AM Harry Wentland <hwentlan@amd.com> wrote:
>
> On 2019-12-02 4:47 p.m., Thomas Anderson wrote:
> > For high-res (8K) or HFR (4K120) displays, using uncompressed pixel
> > formats like YCbCr444 would exceed the bandwidth of HDMI 2.0, so the
> > "interesting" modes would be disabled, leaving only low-res or low
> > framerate modes.
> >
> > This change lowers the pixel encoding to 4:2:2 or 4:2:0 if the max TMDS
> > clock is exceeded. Verified that 8K30 and 4K120 are now available and
> > working with a Samsung Q900R over an HDMI 2.0b link from a Radeon 5700.
> >
> > Signed-off-by: Thomas Anderson <thomasanderson@google.com>
>
> Apologies for the late response.
>
> Thanks for getting high-res modes working on HDMI.
>
> This change is
> Reviewed-by: Harry Wentland <harry.wentland@amd.com>
>

Applied. thanks!

Alex

> Harry
>
> > ---
> > .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 45 ++++++++++---------
> > 1 file changed, 23 insertions(+), 22 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > index 7aac9568d3be..803e59d97411 100644
> > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> > @@ -3356,27 +3356,21 @@ get_output_color_space(const struct dc_crtc_timing *dc_crtc_timing)
> > return color_space;
> > }
> >
> > -static void reduce_mode_colour_depth(struct dc_crtc_timing *timing_out)
> > -{
> > - if (timing_out->display_color_depth <= COLOR_DEPTH_888)
> > - return;
> > -
> > - timing_out->display_color_depth--;
> > -}
> > -
> > -static void adjust_colour_depth_from_display_info(struct dc_crtc_timing *timing_out,
> > - const struct drm_display_info *info)
> > +static bool adjust_colour_depth_from_display_info(
> > + struct dc_crtc_timing *timing_out,
> > + const struct drm_display_info *info)
> > {
> > + enum dc_color_depth depth = timing_out->display_color_depth;
> > int normalized_clk;
> > - if (timing_out->display_color_depth <= COLOR_DEPTH_888)
> > - return;
> > do {
> > normalized_clk = timing_out->pix_clk_100hz / 10;
> > /* YCbCr 4:2:0 requires additional adjustment of 1/2 */
> > if (timing_out->pixel_encoding == PIXEL_ENCODING_YCBCR420)
> > normalized_clk /= 2;
> > /* Adjusting pix clock following on HDMI spec based on colour depth */
> > - switch (timing_out->display_color_depth) {
> > + switch (depth) {
> > + case COLOR_DEPTH_888:
> > + break;
> > case COLOR_DEPTH_101010:
> > normalized_clk = (normalized_clk * 30) / 24;
> > break;
> > @@ -3387,14 +3381,15 @@ static void adjust_colour_depth_from_display_info(struct dc_crtc_timing *timing_
> > normalized_clk = (normalized_clk * 48) / 24;
> > break;
> > default:
> > - return;
> > + /* The above depths are the only ones valid for HDMI. */
> > + return false;
> > }
> > - if (normalized_clk <= info->max_tmds_clock)
> > - return;
> > - reduce_mode_colour_depth(timing_out);
> > -
> > - } while (timing_out->display_color_depth > COLOR_DEPTH_888);
> > -
> > + if (normalized_clk <= info->max_tmds_clock) {
> > + timing_out->display_color_depth = depth;
> > + return true;
> > + }
> > + } while (--depth > COLOR_DEPTH_666);
> > + return false;
> > }
> >
> > static void fill_stream_properties_from_drm_display_mode(
> > @@ -3474,8 +3469,14 @@ static void fill_stream_properties_from_drm_display_mode(
> >
> > stream->out_transfer_func->type = TF_TYPE_PREDEFINED;
> > stream->out_transfer_func->tf = TRANSFER_FUNCTION_SRGB;
> > - if (stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
> > - adjust_colour_depth_from_display_info(timing_out, info);
> > + if (stream->signal == SIGNAL_TYPE_HDMI_TYPE_A) {
> > + if (!adjust_colour_depth_from_display_info(timing_out, info) &&
> > + drm_mode_is_420_also(info, mode_in) &&
> > + timing_out->pixel_encoding != PIXEL_ENCODING_YCBCR420) {
> > + timing_out->pixel_encoding = PIXEL_ENCODING_YCBCR420;
> > + adjust_colour_depth_from_display_info(timing_out, info);
> > + }
> > + }
> > }
> >
> > static void fill_audio_info(struct audio_info *audio_info,
> >
> _______________________________________________
> amd-gfx mailing list
> amd-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx

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