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Subject: Re: [PATCH v4 04/11] drm/bridge: synopsys: dw-hdmi: add bus format
 negociation
References: <20200206191834.6125-1-narmstrong@baylibre.com>
 <20200206191834.6125-5-narmstrong@baylibre.com>
 <5330543.DvuYhMxLoT@jernej-laptop>
From:   Jonas Karlman <jonas@kwiboo.se>
Message-ID: <64b6ef10-b2e2-02f3-56dd-14dd0782a7aa@kwiboo.se>
Date:   Sat, 29 Feb 2020 10:09:14 +0000 (UTC)
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In-Reply-To: <5330543.DvuYhMxLoT@jernej-laptop>
To:     Jernej =?iso-8859-2?q?=A9krabec?= <jernej.skrabec@siol.net>,
        a.hajda@samsung.com, Laurent.pinchart@ideasonboard.com,
        boris.brezillon@collabora.com,
        Neil Armstrong <narmstrong@baylibre.com>
Cc:     linux-amlogic@lists.infradead.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org
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Sender: linux-kernel-owner@vger.kernel.org
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Hi Jernej,

On 2020-02-29 08:42, Jernej Škrabec wrote:
> Hi Neil!
> 
> Dne četrtek, 06. februar 2020 ob 20:18:27 CET je Neil Armstrong napisal(a):
>> Add the atomic_get_output_bus_fmts, atomic_get_input_bus_fmts to negociate
>> the possible output and input formats for the current mode and monitor,
>> and use the negotiated formats in a basic atomic_check callback.
>>
>> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
>> ---
>>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 272 +++++++++++++++++++++-
>>  1 file changed, 268 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c index
>> fec4a4bcd1fe..15048ad694bc 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> @@ -2095,11 +2095,10 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi,
>> struct drm_display_mode *mode)
>> hdmi->hdmi_data.video_mode.mpixelrepetitionoutput = 0;
>>  	hdmi->hdmi_data.video_mode.mpixelrepetitioninput = 0;
>>
>> -	/* TOFIX: Get input format from plat data or fallback to RGB888 */
>>  	if (hdmi->plat_data->input_bus_format)
>>  		hdmi->hdmi_data.enc_in_bus_format =
>>  			hdmi->plat_data->input_bus_format;
>> -	else
>> +	else if (hdmi->hdmi_data.enc_in_bus_format == MEDIA_BUS_FMT_FIXED)
>>  		hdmi->hdmi_data.enc_in_bus_format = 
> MEDIA_BUS_FMT_RGB888_1X24;
>>
>>  	/* TOFIX: Get input encoding from plat data or fallback to none */
>> @@ -2109,8 +2108,8 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct
>> drm_display_mode *mode) else
>>  		hdmi->hdmi_data.enc_in_encoding = 
> V4L2_YCBCR_ENC_DEFAULT;
>>
>> -	/* TOFIX: Default to RGB888 output format */
>> -	hdmi->hdmi_data.enc_out_bus_format = MEDIA_BUS_FMT_RGB888_1X24;
>> +	if (hdmi->hdmi_data.enc_out_bus_format == MEDIA_BUS_FMT_FIXED)
>> +		hdmi->hdmi_data.enc_out_bus_format = 
> MEDIA_BUS_FMT_RGB888_1X24;
>>
>>  	hdmi->hdmi_data.pix_repet_factor = 0;
>>  	hdmi->hdmi_data.hdcp_enable = 0;
>> @@ -2388,6 +2387,267 @@ static const struct drm_connector_helper_funcs
>> dw_hdmi_connector_helper_funcs = .atomic_check =
>> dw_hdmi_connector_atomic_check,
>>  };
>>
>> +/*
>> + * Possible output formats :
>> + * - MEDIA_BUS_FMT_UYYVYY16_0_5X48,
>> + * - MEDIA_BUS_FMT_UYYVYY12_0_5X36,
>> + * - MEDIA_BUS_FMT_UYYVYY10_0_5X30,
>> + * - MEDIA_BUS_FMT_UYYVYY8_0_5X24,
>> + * - MEDIA_BUS_FMT_YUV16_1X48,
>> + * - MEDIA_BUS_FMT_RGB161616_1X48,
>> + * - MEDIA_BUS_FMT_UYVY12_1X24,
>> + * - MEDIA_BUS_FMT_YUV12_1X36,
>> + * - MEDIA_BUS_FMT_RGB121212_1X36,
>> + * - MEDIA_BUS_FMT_UYVY10_1X20,
>> + * - MEDIA_BUS_FMT_YUV10_1X30,
>> + * - MEDIA_BUS_FMT_RGB101010_1X30,
>> + * - MEDIA_BUS_FMT_UYVY8_1X16,
>> + * - MEDIA_BUS_FMT_YUV8_1X24,
>> + * - MEDIA_BUS_FMT_RGB888_1X24,
>> + */
>> +
>> +/* Can return a maximum of 12 possible output formats for a mode/connector
>> */ +#define MAX_OUTPUT_SEL_FORMATS	12
>> +
>> +static u32 *dw_hdmi_bridge_atomic_get_output_bus_fmts(struct drm_bridge
>> *bridge, +					struct 
> drm_bridge_state *bridge_state,
>> +					struct drm_crtc_state 
> *crtc_state,
>> +					struct 
> drm_connector_state *conn_state,
>> +					unsigned int 
> *num_output_fmts)
>> +{
>> +	struct drm_connector *conn = conn_state->connector;
>> +	struct drm_display_info *info = &conn->display_info;
>> +	struct drm_display_mode *mode = &crtc_state->mode;
>> +	u8 max_bpc = conn_state->max_requested_bpc;
>> +	bool is_hdmi2_sink = info->hdmi.scdc.supported ||
>> +			     (info->color_formats & 
> DRM_COLOR_FORMAT_YCRCB420);
>> +	u32 *output_fmts;
>> +	int i = 0;
>> +
>> +	*num_output_fmts = 0;
>> +
>> +	output_fmts = kcalloc(MAX_OUTPUT_SEL_FORMATS, sizeof(*output_fmts),
>> +			      GFP_KERNEL);
>> +	if (!output_fmts)
>> +		return NULL;
>> +
>> +	/*
>> +	 * If the current mode enforces 4:2:0, force the output but format
>> +	 * to 4:2:0 and do not add the YUV422/444/RGB formats
>> +	 */
>> +	if (conn->ycbcr_420_allowed &&
>> +	    (drm_mode_is_420_only(info, mode) ||
>> +	     ())) {
>> +
>> +		/* Order bus formats from 16bit to 8bit if supported */
>> +		if (max_bpc >= 16 && info->bpc == 16 &&
>> +		    (info->hdmi.y420_dc_modes & 
> DRM_EDID_YCBCR420_DC_48))
>> +			output_fmts[i++] = 
> MEDIA_BUS_FMT_UYYVYY16_0_5X48;
>> +
>> +		if (max_bpc >= 12 && info->bpc >= 12 &&
>> +		    (info->hdmi.y420_dc_modes & 
> DRM_EDID_YCBCR420_DC_36))
>> +			output_fmts[i++] = 
> MEDIA_BUS_FMT_UYYVYY12_0_5X36;
>> +
>> +		if (max_bpc >= 10 && info->bpc >= 10 &&
>> +		    (info->hdmi.y420_dc_modes & 
> DRM_EDID_YCBCR420_DC_30))
>> +			output_fmts[i++] = 
> MEDIA_BUS_FMT_UYYVYY10_0_5X30;
>> +
>> +		/* Default 8bit fallback */
>> +		output_fmts[i++] = MEDIA_BUS_FMT_UYYVYY8_0_5X24;
>> +
>> +		*num_output_fmts = i;
>> +
>> +		return output_fmts;
> 
> Driver shouldn't return just yet for case "is_hdmi2_sink && 
> drm_mode_is_420_also(info, mode)", because monitor/TV also supports YCbCr 
> 4:4:4 in that case. IMO YCbCr 4:4:4 should be even prefered. What do you 
> think?

I think we need to have some way for controller driver and userspace to control what
hdmi output format gets selected. I know for a fact that some Samsung TV have issues
with 444 YCbCr modes at 4k 50/60hz but have no problems with 420 modes.
The Samsung TV edid lie and/or the TV is not fully following HDMI specs.

From a personal and mediaplayer userspace perspective I would like to prefer
420/444 YCbCr mode as soon as any yuv drm plane is active and rgb 444 anytime else.

On Rockchip SoCs the display controller cannot output yuv422 to dw-hdmi block,
the optimal output format selection in such case should put yuv422 last.

Maybe dw-hdmi can call a dw-hdmi glue driver callback to get the preferred output format order?

On a side note but related issue, the dw-hdmi format negotiation code should 
probably also filter modes on tmds rate, something like [1].
It is needed to filter out deep color modes that is not supported by the sink or hdmi spec.

[1] https://github.com/Kwiboo/linux-rockchip/commit/fc3df6903384e764ab6ac59879c489cbef55fcbe

Best regards,
Jonas

> 
> Best regards,
> Jernej
> 
>> +	}
>> +
>> +	/*
>> +	 * Order bus formats from 16bit to 8bit and from YUV422 to RGB
>> +	 * if supported. In any case the default RGB888 format is added
>> +	 */
>> +
>> +	if (max_bpc >= 16 && info->bpc == 16) {
>> +		if (info->color_formats & DRM_COLOR_FORMAT_YCRCB444)
>> +			output_fmts[i++] = MEDIA_BUS_FMT_YUV16_1X48;
>> +
>> +		output_fmts[i++] = MEDIA_BUS_FMT_RGB161616_1X48;
>> +	}
>> +
>> +	if (max_bpc >= 12 && info->bpc >= 12) {
>> +		if (info->color_formats & DRM_COLOR_FORMAT_YCRCB422)
>> +			output_fmts[i++] = MEDIA_BUS_FMT_UYVY12_1X24;
>> +
>> +		if (info->color_formats & DRM_COLOR_FORMAT_YCRCB444)
>> +			output_fmts[i++] = MEDIA_BUS_FMT_YUV12_1X36;
>> +
>> +		output_fmts[i++] = MEDIA_BUS_FMT_RGB121212_1X36;
>> +	}
>> +
>> +	if (max_bpc >= 10 && info->bpc >= 10) {
>> +		if (info->color_formats & DRM_COLOR_FORMAT_YCRCB422)
>> +			output_fmts[i++] = MEDIA_BUS_FMT_UYVY10_1X20;
>> +
>> +		if (info->color_formats & DRM_COLOR_FORMAT_YCRCB444)
>> +			output_fmts[i++] = MEDIA_BUS_FMT_YUV10_1X30;
>> +
>> +		output_fmts[i++] = MEDIA_BUS_FMT_RGB101010_1X30;
>> +	}
>> +
>> +	if (info->color_formats & DRM_COLOR_FORMAT_YCRCB422)
>> +		output_fmts[i++] = MEDIA_BUS_FMT_UYVY8_1X16;
>> +
>> +	if (info->color_formats & DRM_COLOR_FORMAT_YCRCB444)
>> +		output_fmts[i++] = MEDIA_BUS_FMT_YUV8_1X24;
>> +
>> +	/* Default 8bit RGB fallback */
>> +	output_fmts[i++] = MEDIA_BUS_FMT_RGB888_1X24;
>> +
>> +	*num_output_fmts = i;
>> +
>> +	return output_fmts;
>> +}
>> +
>> +/*
>> + * Possible input formats :
>> + * - MEDIA_BUS_FMT_RGB888_1X24
>> + * - MEDIA_BUS_FMT_YUV8_1X24
>> + * - MEDIA_BUS_FMT_UYVY8_1X16
>> + * - MEDIA_BUS_FMT_UYYVYY8_0_5X24
>> + * - MEDIA_BUS_FMT_RGB101010_1X30
>> + * - MEDIA_BUS_FMT_YUV10_1X30
>> + * - MEDIA_BUS_FMT_UYVY10_1X20
>> + * - MEDIA_BUS_FMT_UYYVYY10_0_5X30
>> + * - MEDIA_BUS_FMT_RGB121212_1X36
>> + * - MEDIA_BUS_FMT_YUV12_1X36
>> + * - MEDIA_BUS_FMT_UYVY12_1X24
>> + * - MEDIA_BUS_FMT_UYYVYY12_0_5X36
>> + * - MEDIA_BUS_FMT_RGB161616_1X48
>> + * - MEDIA_BUS_FMT_YUV16_1X48
>> + * - MEDIA_BUS_FMT_UYYVYY16_0_5X48
>> + */
>> +
>> +/* Can return a maximum of 4 possible input formats for an output format */
>> +#define MAX_INPUT_SEL_FORMATS	4
>> +
>> +static u32 *dw_hdmi_bridge_atomic_get_input_bus_fmts(struct drm_bridge
>> *bridge, +					struct 
> drm_bridge_state *bridge_state,
>> +					struct drm_crtc_state 
> *crtc_state,
>> +					struct 
> drm_connector_state *conn_state,
>> +					u32 output_fmt,
>> +					unsigned int 
> *num_input_fmts)
>> +{
>> +	u32 *input_fmts;
>> +	int i = 0;
>> +
>> +	*num_input_fmts = 0;
>> +
>> +	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
>> +			     GFP_KERNEL);
>> +	if (!input_fmts)
>> +		return NULL;
>> +
>> +	switch (output_fmt) {
>> +	/* 8bit */
>> +	case MEDIA_BUS_FMT_RGB888_1X24:
>> +		input_fmts[i++] = MEDIA_BUS_FMT_RGB888_1X24;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_YUV8_1X24;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_UYVY8_1X16;
>> +		break;
>> +	case MEDIA_BUS_FMT_YUV8_1X24:
>> +		input_fmts[i++] = MEDIA_BUS_FMT_YUV8_1X24;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_UYVY8_1X16;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_RGB888_1X24;
>> +		break;
>> +	case MEDIA_BUS_FMT_UYVY8_1X16:
>> +		input_fmts[i++] = MEDIA_BUS_FMT_UYVY8_1X16;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_YUV8_1X24;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_RGB888_1X24;
>> +		break;
>> +
>> +	/* 10bit */
>> +	case MEDIA_BUS_FMT_RGB101010_1X30:
>> +		input_fmts[i++] = MEDIA_BUS_FMT_RGB101010_1X30;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_YUV10_1X30;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_UYVY10_1X20;
>> +		break;
>> +	case MEDIA_BUS_FMT_YUV10_1X30:
>> +		input_fmts[i++] = MEDIA_BUS_FMT_YUV10_1X30;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_UYVY10_1X20;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_RGB101010_1X30;
>> +		break;
>> +	case MEDIA_BUS_FMT_UYVY10_1X20:
>> +		input_fmts[i++] = MEDIA_BUS_FMT_UYVY10_1X20;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_YUV10_1X30;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_RGB101010_1X30;
>> +		break;
>> +
>> +	/* 12bit */
>> +	case MEDIA_BUS_FMT_RGB121212_1X36:
>> +		input_fmts[i++] = MEDIA_BUS_FMT_RGB121212_1X36;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_YUV12_1X36;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_UYVY12_1X24;
>> +		break;
>> +	case MEDIA_BUS_FMT_YUV12_1X36:
>> +		input_fmts[i++] = MEDIA_BUS_FMT_YUV12_1X36;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_UYVY12_1X24;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_RGB121212_1X36;
>> +		break;
>> +	case MEDIA_BUS_FMT_UYVY12_1X24:
>> +		input_fmts[i++] = MEDIA_BUS_FMT_UYVY12_1X24;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_YUV12_1X36;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_RGB121212_1X36;
>> +		break;
>> +
>> +	/* 16bit */
>> +	case MEDIA_BUS_FMT_RGB161616_1X48:
>> +		input_fmts[i++] = MEDIA_BUS_FMT_RGB161616_1X48;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_YUV16_1X48;
>> +		break;
>> +	case MEDIA_BUS_FMT_YUV16_1X48:
>> +		input_fmts[i++] = MEDIA_BUS_FMT_YUV16_1X48;
>> +		input_fmts[i++] = MEDIA_BUS_FMT_RGB161616_1X48;
>> +		break;
>> +
>> +	/* 420 */
>> +	case MEDIA_BUS_FMT_UYYVYY8_0_5X24:
>> +	case MEDIA_BUS_FMT_UYYVYY10_0_5X30:
>> +	case MEDIA_BUS_FMT_UYYVYY12_0_5X36:
>> +	case MEDIA_BUS_FMT_UYYVYY16_0_5X48:
>> +		input_fmts[i++] = output_fmt;
>> +		break;
>> +	}
>> +
>> +	*num_input_fmts = i;
>> +
>> +	if (*num_input_fmts == 0) {
>> +		kfree(input_fmts);
>> +		input_fmts = NULL;
>> +	}
>> +
>> +	return input_fmts;
>> +}
>> +
>> +static int dw_hdmi_bridge_atomic_check(struct drm_bridge *bridge,
>> +				       struct drm_bridge_state 
> *bridge_state,
>> +				       struct drm_crtc_state 
> *crtc_state,
>> +				       struct drm_connector_state 
> *conn_state)
>> +{
>> +	struct dw_hdmi *hdmi = bridge->driver_private;
>> +
>> +	dev_dbg(hdmi->dev, "selected output format %x\n",
>> +			bridge_state->output_bus_cfg.format);
>> +
>> +	hdmi->hdmi_data.enc_out_bus_format =
>> +			bridge_state->output_bus_cfg.format;
>> +
>> +	dev_dbg(hdmi->dev, "selected input format %x\n",
>> +			bridge_state->input_bus_cfg.format);
>> +
>> +	hdmi->hdmi_data.enc_in_bus_format =
>> +			bridge_state->input_bus_cfg.format;
>> +
>> +	return 0;
>> +}
>> +
>>  static int dw_hdmi_bridge_attach(struct drm_bridge *bridge)
>>  {
>>  	struct dw_hdmi *hdmi = bridge->driver_private;
>> @@ -2499,6 +2759,9 @@ static const struct drm_bridge_funcs
>> dw_hdmi_bridge_funcs = { .atomic_reset = drm_atomic_helper_bridge_reset,
>>  	.attach = dw_hdmi_bridge_attach,
>>  	.detach = dw_hdmi_bridge_detach,
>> +	.atomic_check = dw_hdmi_bridge_atomic_check,
>> +	.atomic_get_output_bus_fmts = 
> dw_hdmi_bridge_atomic_get_output_bus_fmts,
>> +	.atomic_get_input_bus_fmts = 
> dw_hdmi_bridge_atomic_get_input_bus_fmts,
>>  	.enable = dw_hdmi_bridge_enable,
>>  	.disable = dw_hdmi_bridge_disable,
>>  	.mode_set = dw_hdmi_bridge_mode_set,
>> @@ -2963,6 +3226,7 @@ __dw_hdmi_probe(struct platform_device *pdev,
>>
>>  	hdmi->bridge.driver_private = hdmi;
>>  	hdmi->bridge.funcs = &dw_hdmi_bridge_funcs;
>> +
>>  #ifdef CONFIG_OF
>>  	hdmi->bridge.of_node = pdev->dev.of_node;
>>  #endif
> 
> 
> 
>