Re: [PATCH 16/32] drm/amd/display: Add Support for HDMI Compliance Automation

[Nicolas Frattaroli <nicolas.frattaroli@collabora.com>]

On Wednesday, 10 June 2026 11:45:00 Central European Summer Time Chenyu Chen wrote:
> From: Fangzhi Zuo <Jerry.Zuo@amd.com>
> 
> Add support to get DUT trained at FRL link rate when working with
> Teledyne M41h compliance automation.
> 
> Reviewed-by: Alex Hung <alex.hung@amd.com>
> Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
> Signed-off-by: Chenyu Chen <chen-yu.chen@amd.com>
> ---
>  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h |  3 +
>  .../display/amdgpu_dm/amdgpu_dm_connector.c   |  5 ++
>  .../amd/display/amdgpu_dm/amdgpu_dm_debugfs.c | 67 ++++++++++++++++++-
>  .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c |  6 ++
>  4 files changed, 80 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> index 2940dd5b7348..ba1e11e144f2 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
> @@ -877,6 +877,9 @@ struct amdgpu_dm_connector {
>  	unsigned int hdmi_hpd_debounce_delay_ms;
>  	struct delayed_work hdmi_hpd_debounce_work;
>  	struct dc_sink *hdmi_prev_sink;
> +
> +	/* HDMI compliance automation */
> +	bool hdmi_comp_auto;
>  };
>  
>  static inline void amdgpu_dm_set_mst_status(uint8_t *status,
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> index 6ef257622f1a..59091ee32099 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_connector.c
> @@ -573,6 +573,11 @@ void amdgpu_dm_update_connector_after_detect(
>  		amdgpu_dm_update_freesync_caps(connector, aconnector->drm_edid, true);
>  		amdgpu_dm_update_connector_ext_caps(aconnector);
>  		dm_set_panel_type(aconnector);
> +
> +		if (aconnector->hdmi_comp_auto) {
> +			if (sink->sink_signal != SIGNAL_TYPE_HDMI_FRL)
> +				sink->sink_signal = SIGNAL_TYPE_HDMI_FRL;
> +		}
>  	} else {
>  		hdmi_cec_unset_edid(aconnector);
>  		drm_dp_cec_unset_edid(&aconnector->dm_dp_aux.aux);
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
> index 096a855a7304..95a56e39f452 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
> @@ -2982,6 +2982,64 @@ static ssize_t hdmi_cec_state_write(struct file *f, const char __user *buf,
>  	return size;
>  }
>  
> +/**
> + * hdmi_automation_enable - Enable/Disable HDMI automation feature
> + * @f: file structure.
> + * @buf: userspace buffer. set to '1' to enable; '0' to disable automation feature.
> + * @size: size of buffer from userpsace.
> + * @pos: unused.
> + *
> + * Return size on success, error code on failure
> + */
> +static ssize_t hdmi_automation_enable(struct file *f, const char __user *buf,
> +	size_t size, loff_t *pos)
> +{
> +	struct amdgpu_dm_connector *aconnector = file_inode(f)->i_private;
> +	char *wr_buf = NULL;
> +	const uint32_t wr_buf_size = 40;
> +	int max_param_num = 1;
> +	uint8_t param_nums = 0;
> +	long param[2];
> +	bool hdmi_comp_auto;
> +
> +	if (size == 0)
> +		return -EINVAL;
> +
> +	wr_buf = kcalloc(wr_buf_size, sizeof(char), GFP_KERNEL);
> +	if (!wr_buf)
> +		return -ENOSPC;
> +
> +	if (parse_write_buffer_into_params(wr_buf, wr_buf_size,
> +					   (long *)param, buf,
> +					   max_param_num,
> +					   &param_nums)) {
> +		kfree(wr_buf);
> +		return -EINVAL;
> +	}
> +
> +	if (param_nums <= 0) {
> +		kfree(wr_buf);
> +		DRM_DEBUG_DRIVER("user data not be read\n");
> +		return -EINVAL;
> +	}
> +
> +	switch (param[0]) {
> +	case 0:
> +		hdmi_comp_auto = false;
> +		break;
> +	case 1:
> +	default:
> +		hdmi_comp_auto = true;
> +		break;
> +	}
> +
> +	/* Persist setting across sink re-detection/hotplug. */
> +	aconnector->hdmi_comp_auto = hdmi_comp_auto;
> +
> +	kfree(wr_buf);
> +	return size;
> +}
> +
>  DEFINE_SHOW_ATTRIBUTE(dp_dsc_fec_support);
>  DEFINE_SHOW_ATTRIBUTE(dmub_fw_state);
>  DEFINE_SHOW_ATTRIBUTE(dmub_tracebuffer);
> @@ -3099,6 +3157,12 @@ static const struct file_operations dp_mst_link_settings_debugfs_fops = {
>  	.llseek = default_llseek
>  };
>  
> +static const struct file_operations hdmi_automation_debugfs_fops = {
> +	.owner = THIS_MODULE,
> +	.write = hdmi_automation_enable,
> +	.llseek = default_llseek
> +};
> +

I really don't understand why this can't just be a DEFINE_DEBUGFS_ATTRIBUTE,
and then you can replace the overcomplicated hdmi_automation_enable() with
just simple setter and getter functions that already receive the parameter
of the right type.

>  static const struct {
>  	char *name;
>  	const struct file_operations *fops;
> @@ -3131,7 +3195,8 @@ static const struct {
>  	const struct file_operations *fops;
>  } hdmi_debugfs_entries[] = {
>  		{"hdcp_sink_capability", &hdcp_sink_capability_fops},
> -		{"hdmi_cec_state", &hdmi_cec_state_fops}
> +		{"hdmi_cec_state", &hdmi_cec_state_fops},
> +		{"hdmi_automation", &hdmi_automation_debugfs_fops}
>  };
>  
>  /*
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> index a2d0bb34e639..6350212b9a66 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
> @@ -193,6 +193,12 @@ enum dc_edid_status dm_helpers_parse_edid_caps(
>  					__func__, connector->name, edid_caps->frl_dsc_10bpc, edid_caps->frl_dsc_12bpc, \
>  					edid_caps->frl_dsc_all_bpp, edid_caps->frl_dsc_native_420, edid_caps->frl_dsc_max_slices, \
>  					edid_caps->frl_dsc_max_frl_rate, edid_caps->frl_dsc_total_chunk_kbytes);
> +		if (aconnector->hdmi_comp_auto) {
> +			edid_caps->panel_patch.hdmi_comp_auto = true;
> +			link->ctx->dc->debug.force_frl_max = true;
> +			link->ctx->dc->debug.force_frl_dsc = true;
> +			drm_dbg_driver(connector->dev, "%s: HDMI_FRL [%s] hdmi_comp_auto --> enabled\n", __func__, connector->name);
> +		}
>  	}
>  
>  	apply_edid_quirks(link, edid_buf, edid_caps);
>