OK3588 5.10.66 Buildroot Fixed HDMI Resolution

Document classification: □ Top secret □ Secret □ Internal information ■ Open

Copyright

The copyright of this manual belongs to Baoding Folinx Embedded Technology Co., Ltd. Without the written permission of our company, no organizations or individuals have the right to copy, distribute, or reproduce any part of this manual in any form, and violators will be held legally responsible.
Forlinx adheres to copyrights of all graphics and texts used in all publications in original or license-free forms.
The drivers and utilities used for the components are subject to the copyrights of the respective manufacturers. The license conditions of the respective manufacturer are to be adhered to. Related license expenses for the operating system and applications should be calculated/declared separately by the related party or its representatives.

Note: All modifications are made in the file/OK3588-linux-source/kernel/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c

1. Choose HDMI as the screen in U-Boot;

2. Modify DW-HDMI. C films;

Add edid = NULL;

static int dw_hdmi_connector_get_modes(struct drm_connector *connector)
{
struct dw_hdmi *hdmi = container_of(connector, struct dw_hdmi,
     connector);
struct hdr_static_metadata *metedata =
&connector->hdr_sink_metadata.hdmi_type1;
struct edid *edid;
struct drm_display_mode *mode;
struct drm_display_info *info = &connector->display_info;
int i, ret = 0;

memset(metedata, 0, sizeof(*metedata));
if (!hdmi->ddc)
return 0;

edid = drm_get_edid(connector, hdmi->ddc);
edid = NULL   //Add here
if (edid) {
dev_dbg(hdmi->dev, "got edid: width[%d] x height[%d]\n",
edid->width_cm, edid->height_cm);

hdmi->support_hdmi = drm_detect_hdmi_monitor(edid);
hdmi->sink_has_audio = drm_detect_monitor_audio(edid);
drm_connector_update_edid_property(connector, edid);
cec_notifier_set_phys_addr_from_edid(hdmi->cec_notifier, edid);
ret = drm_add_edid_modes(connector, edid);
dw_hdmi_update_hdr_property(connector);
kfree(edid);
} else {
hdmi->support_hdmi = true;
hdmi->sink_has_audio = true;

for (i = 0; i < ARRAY_SIZE(dw_hdmi_default_modes); i++) {
const struct drm_display_mode *ptr =
&dw_hdmi_default_modes[i];

mode = drm_mode_duplicate(connector->dev, ptr);
if (mode) {
if (!i) {
mode->type = DRM_MODE_TYPE_PREFERRED;
mode->picture_aspect_ratio =
HDMI_PICTURE_ASPECT_NONE;
}
drm_mode_probed_add(connector, mode);
ret++;
}
}
info->edid_hdmi_dc_modes = 0;
info->hdmi.y420_dc_modes = 0;
info->color_formats = 0;

dev_info(hdmi->dev, "failed to get edid\n");
}
dw_hdmi_check_output_type_changed(hdmi);

return ret;
}

3. Fixed resolution

In the file OK3588-linux-source/kernel/drivers/gpu/drm/bridge/synopsys/dw-hdmi-qp.c:

Locate static const struct drm_display_mode dw_hdmi_default_modes[] = {}; and comment out all existing resolutions within this array. Other resolution definitions can be found in the file OK3588-linux-source/kernel/drivers/gpu/drm/drm_edid.c. Select the desired mode(s) from there.

Add the chosen mode(s) into the static const struct drm_display_mode dw_hdmi_default_modes[] = {}; array in the dw-hdmi-qp.c file.

static const struct drm_display_mode dw_hdmi_default_modes[] = {
/* 108 - 1920x1080@60Hz */
{ DRM_MODE("1920x1080", DRM_MODE_TYPE_DRIVER, 148500, 1920, 2008,
2052, 2200, 0, 1080, 1084, 1089, 1125, 0,
DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC), 
.vrefresh = 60, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_64_27, }, 
/* 
4 - 1280x720@60Hz 16:9 
{ DRM_MODE("1280x720", DRM_MODE_TYPE_DRIVER, 74250, 1280, 1390,
   1430, 1650, 0, 720, 725, 730, 750, 0,
   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),
  .vrefresh = 60, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_16_9, },
 16 - 1920x1080@60Hz 16:9 
{ DRM_MODE("1920x1080", DRM_MODE_TYPE_DRIVER, 148500, 1920, 2008,
   2052, 2200, 0, 1080, 1084, 1089, 1125, 0,
   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),
  .vrefresh = 60, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_16_9, },
 31 - 1920x1080@50Hz 16:9 
{ DRM_MODE("1920x1080", DRM_MODE_TYPE_DRIVER, 148500, 1920, 2448,
   2492, 2640, 0, 1080, 1084, 1089, 1125, 0,
   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),
  .vrefresh = 50, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_16_9, },
 19 - 1280x720@50Hz 16:9 
{ DRM_MODE("1280x720", DRM_MODE_TYPE_DRIVER, 74250, 1280, 1720,
   1760, 1980, 0, 720, 725, 730, 750, 0,
   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC),
  .vrefresh = 50, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_16_9, },
 0x10 - 1024x768@60Hz 
{ DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER, 65000, 1024, 1048,
   1184, 1344, 0,  768, 771, 777, 806, 0,
   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) },
 17 - 720x576@50Hz 4:3 
{ DRM_MODE("720x576", DRM_MODE_TYPE_DRIVER, 27000, 720, 732,
   796, 864, 0, 576, 581, 586, 625, 0,
   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC),
  .vrefresh = 50, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_4_3, },
 2 - 720x480@60Hz 4:3 
{ DRM_MODE("720x480", DRM_MODE_TYPE_DRIVER, 27000, 720, 736,
   798, 858, 0, 480, 489, 495, 525, 0,
   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC),
  .vrefresh = 60, .picture_aspect_ratio = HDMI_PICTURE_ASPECT_4_3, },
*/   //Comment out, leaving only the desired resolution
};

4. Compile the Kernel separately

Use ./build.sh kernel to compile the kernel individually, which will generate the /kernel/boot.img file. Flash the boot.img file separately.