[PATCH] drm/amd/display: Fix sending VSC (+ colorimetry) packets for DP/eDP displays without PSR

[Joshua Ashton]

 From the issue:

```
Thank you for for fixing this!
I built a custom kernel with this patch on the fedora rawhide kernel 
(6.7.0-0.rc8.61.fc40.x86_64) and now the colors look correct. SDR 
content is now displayed as sRGB and HDR/WCG content can use the full 
capabilities of the display.
I currently don't have a desktop mail client installed to comment on the 
mailing list directly, so I'll post it here (not sure if it counts or 
matters 😀 )

Tested-By: Simon Berz <simon at berz.me>
```

- Joshie 🐸✨

On 1/1/24 18:28, Joshua Ashton wrote:
> The check for sending the vsc infopacket to the display was gated behind
> PSR (Panel Self Refresh) being enabled.
> 
> The vsc infopacket also contains the colorimetry (specifically the
> container color gamut) information for the stream on modern DP.
> 
> PSR is typically only supported on mobile phone eDP displays, thus this
> was not getting sent for typical desktop monitors or TV screens.
> 
> This functionality is needed for proper HDR10 functionality on DP as it
> wants BT2020 RGB/YCbCr for the container color space.
> 
> Signed-off-by: Joshua Ashton <joshua at froggi.es>
> 
> Cc: Harry Wentland <harry.wentland at amd.com>
> Cc: Xaver Hugl <xaver.hugl at gmail.com>
> Cc: Melissa Wen <mwen at igalia.com>
> ---
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c   |  8 +++++---
>   .../amd/display/modules/info_packet/info_packet.c   | 13 ++++++++-----
>   2 files changed, 13 insertions(+), 8 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 2845c884398e..6dff56408bf4 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -6233,8 +6233,9 @@ create_stream_for_sink(struct drm_connector *connector,
>   
>   	if (stream->signal == SIGNAL_TYPE_HDMI_TYPE_A)
>   		mod_build_hf_vsif_infopacket(stream, &stream->vsp_infopacket);
> -
> -	if (stream->link->psr_settings.psr_feature_enabled || stream->link->replay_settings.replay_feature_enabled) {
> +	else if (stream->signal == SIGNAL_TYPE_DISPLAY_PORT ||
> +			 stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST ||
> +			 stream->signal == SIGNAL_TYPE_EDP) {
>   		//
>   		// should decide stream support vsc sdp colorimetry capability
>   		// before building vsc info packet
> @@ -6250,8 +6251,9 @@ create_stream_for_sink(struct drm_connector *connector,
>   		if (stream->out_transfer_func->tf == TRANSFER_FUNCTION_GAMMA22)
>   			tf = TRANSFER_FUNC_GAMMA_22;
>   		mod_build_vsc_infopacket(stream, &stream->vsc_infopacket, stream->output_color_space, tf);
> -		aconnector->psr_skip_count = AMDGPU_DM_PSR_ENTRY_DELAY;
>   
> +		if (stream->link->psr_settings.psr_feature_enabled)
> +			aconnector->psr_skip_count = AMDGPU_DM_PSR_ENTRY_DELAY;
>   	}
>   finish:
>   	dc_sink_release(sink);
> diff --git a/drivers/gpu/drm/amd/display/modules/info_packet/info_packet.c b/drivers/gpu/drm/amd/display/modules/info_packet/info_packet.c
> index 84f9b412a4f1..738ee763f24a 100644
> --- a/drivers/gpu/drm/amd/display/modules/info_packet/info_packet.c
> +++ b/drivers/gpu/drm/amd/display/modules/info_packet/info_packet.c
> @@ -147,12 +147,15 @@ void mod_build_vsc_infopacket(const struct dc_stream_state *stream,
>   	}
>   
>   	/* VSC packet set to 4 for PSR-SU, or 2 for PSR1 */
> -	if (stream->link->psr_settings.psr_version == DC_PSR_VERSION_SU_1)
> -		vsc_packet_revision = vsc_packet_rev4;
> -	else if (stream->link->replay_settings.config.replay_supported)
> +	if (stream->link->psr_settings.psr_feature_enabled) {
> +		if (stream->link->psr_settings.psr_version == DC_PSR_VERSION_SU_1)
> +			vsc_packet_revision = vsc_packet_rev4;
> +		else if (stream->link->psr_settings.psr_version == DC_PSR_VERSION_1)
> +			vsc_packet_revision = vsc_packet_rev2;
> +	}
> +
> +	if (stream->link->replay_settings.config.replay_supported)
>   		vsc_packet_revision = vsc_packet_rev4;
> -	else if (stream->link->psr_settings.psr_version == DC_PSR_VERSION_1)
> -		vsc_packet_revision = vsc_packet_rev2;
>   
>   	/* Update to revision 5 for extended colorimetry support */
>   	if (stream->use_vsc_sdp_for_colorimetry)