What pass connector_id in lv_linux_drm_set_file on first time setup?

[Coloryr]

LVGL version

v9.1.0

What happened?

lv_linux_drm_set_file is need connector_id, but I can't get it anywhere, it's design defects?
I try 0, itn's work.

How to reproduce?

    lv_init();

    lv_display_t * display = lv_linux_drm_create();

    lv_linux_drm_set_file(display, "/dev/dri/card0", 0);

[Coloryr]

[Coloryr]

If there is no first call to lv_linux_drm_set_file, then fb is -1, and the connector_id cannot be obtained. Only after calling lv_linux_drm_set_file can fb have a value and the connector_id can be obtained, so I don't know how much this value should be passed in.

[kisvegabor]

The DRM driver was contributed @MiSimon. Michael, could you take a look at this issue?

[Coloryr]

I found that my device can pass 113, and this value will not change.

[Coloryr]

But I encountered a more strange problem.

VID_20240430_083854.1.mp4

[kisvegabor]

But I encountered a more strange problem.

It's interesting because this issue usually happens in LV_DISPLAY_RENDER_MODE_PARTIALwhen the rendered image is copied incorrectly. However the DRM driver uses LV_DISPLAY_RENDER_MODE_DIRECT.

Maybe a color format mismatch? In lv_linux_drm_set_file please call lv_display_set_color_fromat(disp, LV_COLOR_FORMAT_...) explicitly to be sure that the LVGL display's color format is correct.

[Coloryr]

Only LV_COLOR_FORMAT_NATIVE display and refresh, other fromat can only display the first frame, or not display it, and there will be the situation I saw in my previous video.

[MiSimon]

The DRM driver was contributed @MiSimon. Michael, could you take a look at this issue?

@kisvegabor I was just the last one who touched it as I prepared the UEFI CI makefile. I think the code comes from the lv_drivers repo.

[kisvegabor]

Sorry @MiSimon, I think @niklasf should be the one who can help us out. 🤞

[niklasf]

Hi. In most cases usage will look like:

lv_display_t * display = lv_linux_drm_create();
lv_linux_drm_set_file(display, "/dev/dri/card0", -1 /* use first connector */);

If that's not good, drm_info is a nice tool to enumerate connectors and their modes and properties. For example, the output might look like:

Node: /dev/dri/card0                <-- path
├───Driver: vc4 (Broadcom VC4 graphics) version 0.0.0 (20140616)
│   ├───DRM_CLIENT_CAP_STEREO_3D supported
│   ├───DRM_CLIENT_CAP_UNIVERSAL_PLANES supported
│   ├───DRM_CLIENT_CAP_ATOMIC supported
[...]
│   ├───DRM_CAP_ADDFB2_MODIFIERS = 1
│   ├───DRM_CAP_PAGE_FLIP_TARGET = 0
│   ├───DRM_CAP_CRTC_IN_VBLANK_EVENT = 1
│   ├───DRM_CAP_SYNCOBJ = 1
│   └───DRM_CAP_SYNCOBJ_TIMELINE = 0
├───Device: platform brcm,bcm2835-vc4
├───Framebuffer size
│   ├───Width: [0, 2048]
│   └───Height: [0, 2048]
├───Connectors
│   ├───Connector 0
│   │   ├───Object ID: 32          <-- the connector id i could have used instead of -1
│   │   ├───Type: HDMI-A
│   │   ├───Status: connected
│   │   ├───Physical size: 530x300 mm
│   │   ├───Subpixel: unknown
│   │   ├───Encoders: {0}
│   │   ├───Modes
│   │   │   ├───1920x1080@60.00 preferred driver phsync pvsync
│   │   │   ├───1920x1080@60.00 driver phsync pvsync 16:9
[...]
│   │   │   └───720x400@70.08 driver nhsync pvsync
│   │   └───Properties
│   │       ├───"EDID" (immutable): blob = 294
│   │       ├───"DPMS": enum {On, Standby, Suspend, Off} = On
│   │       ├───"link-status": enum {Good, Bad} = Good
│   │       ├───"non-desktop" (immutable): range [0, 1] = 0
│   │       ├───"TILE" (immutable): blob = 0
│   │       ├───"CRTC_ID" (atomic): object CRTC = 90
│   │       ├───"Colorspace": enum {Default, SMPTE_170M_YCC, BT709_YCC, XVYCC_601, XVYCC_709, SYCC_601, opYCC_601, opRGB, BT2020_CYCC, BT2020_RGB, BT2020_YCC, DCI-P3_RGB_D65, DCI-P3_RGB_Theater} = Default
│   │       ├───"left margin": range [0, 100] = 0
│   │       ├───"right margin": range [0, 100] = 0
│   │       ├───"top margin": range [0, 100] = 0
│   │       ├───"bottom margin": range [0, 100] = 0
│   │       ├───"max bpc": range [8, 12] = 8
│   │       ├───"Broadcast RGB": enum {Automatic, Full, Limited 16:235} = Automatic
│   │       └───"Output format": enum {Automatic, RGB, YCbCr 4:2:2, YCbCr 4:4:4} = Automatic
│   └───Connector 1
│       ├───Object ID: 57
[...]

[kisvegabor]

Thank you for the info! I think it would be important to document for the future DRM users. Would you mind adding a brief guide about it here?

[Coloryr]

Thanks, -1 is work, but still like this.

But I encountered a more strange problem.

VID_20240430_083854.1.mp4

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