Re: [PATCH v17 4/6] drm/bridge: dw-hdmi: handle unusable or non-configured CSC module

From: H. Nikolaus Schaller
Date: Thu Apr 07 2022 - 07:16:47 EST


Hi Neil,

> Am 07.04.2022 um 10:28 schrieb Neil Armstrong <narmstrong@xxxxxxxxxxxx>:
>
> Hi,
>
> On 06/04/2022 18:26, H. Nikolaus Schaller wrote:
>> From: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
>> The dw-hdmi integrates an optional Color Space Conversion feature used
>> to handle color-space conversions.
>> On some platforms, the CSC isn't built-in or non-functional.
>> This adds the necessary code to disable the CSC functionality
>> and limit the bus format negotiation to force using the same
>> input bus format as the output bus format.
>> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
>> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
>> ---
>> drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 100 +++++++++++++++-------
>> drivers/gpu/drm/bridge/synopsys/dw-hdmi.h | 1 +
>> include/drm/bridge/dw_hdmi.h | 1 +
>> 3 files changed, 71 insertions(+), 31 deletions(-)
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> index f50af40e10340..b5a665c5e406e 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>> @@ -158,6 +158,8 @@ struct dw_hdmi {
>> struct hdmi_data_info hdmi_data;
>> const struct dw_hdmi_plat_data *plat_data;
>> + bool csc_available; /* indicates if the CSC engine is usable */
>> +
>> int vic;
>> u8 edid[HDMI_EDID_LEN];
>> @@ -1009,9 +1011,10 @@ static int is_color_space_interpolation(struct dw_hdmi *hdmi)
>> static bool is_csc_needed(struct dw_hdmi *hdmi)
>> {
>> - return is_color_space_conversion(hdmi) ||
>> - is_color_space_decimation(hdmi) ||
>> - is_color_space_interpolation(hdmi);
>> + return hdmi->csc_available &&
>> + (is_color_space_conversion(hdmi) ||
>> + is_color_space_decimation(hdmi) ||
>> + is_color_space_interpolation(hdmi));
>> }
>> static void dw_hdmi_update_csc_coeffs(struct dw_hdmi *hdmi)
>> @@ -1064,6 +1067,9 @@ static void hdmi_video_csc(struct dw_hdmi *hdmi)
>> int interpolation = HDMI_CSC_CFG_INTMODE_DISABLE;
>> int decimation = 0;
>> + if (!hdmi->csc_available)
>> + return;
>> +
>> /* YCC422 interpolation to 444 mode */
>> if (is_color_space_interpolation(hdmi))
>> interpolation = HDMI_CSC_CFG_INTMODE_CHROMA_INT_FORMULA1;
>> @@ -2665,6 +2671,7 @@ static u32 *dw_hdmi_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
>> u32 output_fmt,
>> unsigned int *num_input_fmts)
>> {
>> + struct dw_hdmi *hdmi = bridge->driver_private;
>> u32 *input_fmts;
>> unsigned int i = 0;
>> @@ -2683,62 +2690,81 @@ static u32 *dw_hdmi_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
>> /* 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;
>> + if (hdmi->csc_available) {
>> + 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;
>> + if (hdmi->csc_available) {
>> + 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;
>> + if (hdmi->csc_available) {
>> + 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;
>> + if (hdmi->csc_available) {
>> + 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;
>> + if (hdmi->csc_available) {
>> + 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;
>> + if (hdmi->csc_available) {
>> + 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;
>> + if (hdmi->csc_available) {
>> + 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;
>> + if (hdmi->csc_available) {
>> + 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;
>> + if (hdmi->csc_available) {
>> + 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;
>> + if (hdmi->csc_available)
>> + 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;
>> + if (hdmi->csc_available)
>> + input_fmts[i++] = MEDIA_BUS_FMT_YUV16_1X48;
>> break;
>> /*YUV 4:2:0 */
>> @@ -2767,15 +2793,24 @@ static int dw_hdmi_bridge_atomic_check(struct drm_bridge *bridge,
>> {
>> struct dw_hdmi *hdmi = bridge->driver_private;
>> - hdmi->hdmi_data.enc_out_bus_format =
>> - bridge_state->output_bus_cfg.format;
>> + if (!hdmi->csc_available &&
>> + bridge_state->output_bus_cfg.format != bridge_state->input_bus_cfg.format) {
>> + dev_warn(hdmi->dev, "different input format 0x%04x & output format 0x%04x while CSC isn't usable, fallback to safe format\n",
>> + bridge_state->input_bus_cfg.format,
>> + bridge_state->output_bus_cfg.format);
>> + hdmi->hdmi_data.enc_out_bus_format = MEDIA_BUS_FMT_FIXED;
>> + hdmi->hdmi_data.enc_in_bus_format = MEDIA_BUS_FMT_FIXED;
>> + } else {
>> + hdmi->hdmi_data.enc_out_bus_format =
>> + bridge_state->output_bus_cfg.format;
>> - hdmi->hdmi_data.enc_in_bus_format =
>> - bridge_state->input_bus_cfg.format;
>> + hdmi->hdmi_data.enc_in_bus_format =
>> + bridge_state->input_bus_cfg.format;
>> - dev_dbg(hdmi->dev, "input format 0x%04x, output format 0x%04x\n",
>> - bridge_state->input_bus_cfg.format,
>> - bridge_state->output_bus_cfg.format);
>> + dev_dbg(hdmi->dev, "input format 0x%04x, output format 0x%04x\n",
>> + bridge_state->input_bus_cfg.format,
>> + bridge_state->output_bus_cfg.format);
>> + }
>> return 0;
>> }
>> @@ -3481,6 +3516,9 @@ struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
>> hdmi->cec = platform_device_register_full(&pdevinfo);
>> }
>> + /* Get CSC useability from config0 register and permit override for platforms */
>> + hdmi->csc_available = !plat_data->disable_csc || (config0 & HDMI_CONFIG0_CSC);
>> +
>> drm_bridge_add(&hdmi->bridge);
>> return hdmi;
>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
>> index 1999db05bc3b2..279722e4d1898 100644
>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.h
>> @@ -541,6 +541,7 @@ enum {
>> /* CONFIG0_ID field values */
>> HDMI_CONFIG0_I2S = 0x10,
>> + HDMI_CONFIG0_CSC = 0x04,
>> HDMI_CONFIG0_CEC = 0x02,
>> /* CONFIG1_ID field values */
>> diff --git a/include/drm/bridge/dw_hdmi.h b/include/drm/bridge/dw_hdmi.h
>> index 2a1f85f9a8a3f..b2f689cbe864c 100644
>> --- a/include/drm/bridge/dw_hdmi.h
>> +++ b/include/drm/bridge/dw_hdmi.h
>> @@ -157,6 +157,7 @@ struct dw_hdmi_plat_data {
>> unsigned long mpixelclock);
>> unsigned int disable_cec : 1;
>> + unsigned int disable_csc : 1;
>> };
>> struct dw_hdmi *dw_hdmi_probe(struct platform_device *pdev,
>
> Is this really still needed now you filter correctly the possible
> modes in patch 1 ?

I had not tried to remove them because they were needed in [PATCH v16]
but indeed they are no longer needed. Something (which I personally
don't understand) may have blocked it so far, but it is not worth
further analyses.

So we can shrink the series and no need to touch drm/bridge: dw-hdmi:
any more!

I'll now post a new v18.

BR and thanks for review,
Nikolaus