Hello, We are trying to bring up a custom 5.0" 480x854 MIPI DSI panel (2 lanes, ST7102 driver, model LX50FWS40258-V0(S)) on a ROCK 3C. The screen stays completely black, and even the panel’s built-in self-test (BIST, started by a DSI command at the end of the init sequence) shows nothing. SETUP - Board: ROCK 3C (Radxa OS; exact image and kernel version will follow in a reply together with the log) - Connection: custom adapter board from the ROCK 3C 15-pin DSI connector (signals named MIPI_DSI_TX1_D0/D1/CLK, supply VCC_MIPI) to the panel’s 40-pin FPC - A separate module on the adapter provides 1.8 V (IOVCC) and 18 V (backlight). VDD measured at 3.3 V. - Reset: no GPIO is used. It is an RC network (10 kOhm to 1.8 V, 100 nF to ground). PANEL NODE (from the panel maker; it was written for a ROCK 3B) &dsi0 { status = “okay”; #address-cells = <1>; #size-cells = <0>; panel@0 { compatible = “simple-panel-dsi”; reg = <0>; reset-gpios = <&gpioX RK_PXX GPIO_ACTIVE_LOW>; /* placeholder, we do not use a reset GPIO */ prepare-delay-ms = <10>; reset-delay-ms = <20>; init-delay-ms = <130>; enable-delay-ms = <20>; unprepare-delay-ms = <20>; disable-delay-ms = <20>; width-mm = <62>; height-mm = <110>; bpc = <8>; bus-format = <0x100a>; dsi,flags = <(MIPI_DSI_MODE_VIDEO | MIPI_DSI_MODE_VIDEO_BURST | MIPI_DSI_MODE_LPM | MIPI_DSI_MODE_EOT_PACKET)>; dsi,format = <MIPI_DSI_FMT_RGB888>; dsi,lanes = <2>; panel-init-sequence = [ …omitted, the last command starts the panel BIST… ]; display-timings { native-mode = <&timing0>; timing0: timing0 { clock-frequency = <39000000>; hactive = <480>; hfront-porch = <40>; hsync-len = <2>; hback-porch = <40>; vactive = <854>; vfront-porch = <300>; vsync-len = <2>; vback-porch = <9>; hsync-active = <0>; vsync-active = <0>; de-active = <0>; pixelclk-active = <0>; }; }; }; }; WHAT WE SEE - Screen fully black, BIST shows nothing - Voltages at the panel connector: IOVCC 1.8 V, VDD 3.3 V, RESET 1.8 V (idle level) - Startup log (dmesg) to follow in a reply QUESTIONS 1. Our connector signals are named MIPI_DSI_TX1, but the file above enables &dsi0. Which device tree node corresponds to it on the ROCK 3C (dsi1?), and which other nodes must be enabled (PHY, VOP routing)? 2. Does the Radxa image power the DSI connector supply (VCC_MIPI) by default? If it is switched by a GPIO or regulator, which one? 3. Is there a working example overlay for a custom panel with its own init sequence on the ROCK 3C that we could use as a reference? 4. Any known problems sending the panel init commands (low-power mode) on the RK3566 with this kernel? Thank you for any hints.
Radxa’s ROCK 3C display examples in the stable-4.19-rock3 kernel branch enable dsi1 with video_phy1 and the dsi1_in_vp0 / route_dsi1 path. The rock-3c-raspberrypi-7inch-touchscreen overlay also defines vcc_mipi as a 3.3 V fixed regulator using GPIO0 RK_PC7, with regulator-always-on set. These are examples for those displays and that kernel branch, not confirmation of the supply or configuration for your custom panel. Which kernel version and image are you using?
Hey
we are not using kernal version , we are using the standard Android image available on the radxa website, submitted
Can u pls guide how we can do this