gx_mem: allocation failed (size=4194304) → Increase CMA size in bootargs: cma=384M or adjust per-pool sizes in device tree. 7. Device Tree Bindings (Example for GX350) &gx_vpu compatible = "nationalchip,gx350-vpu"; reg = <0x0 0xf1000000 0x0 0x4000>; interrupts = <0 33 4>; clocks = <&clkc GX350_CLK_VPU>, <&clkc GX350_CLK_VPU_AXI>; clock-names = "core", "bus"; firmware-name = "gx_vpu_fw.bin"; memory-region = <&vpu_mem>; ; &gx_disp compatible = "nationalchip,gx350-disp"; reg = <0x0 0xf0000000 0x0 0x2000>; interrupts = <0 25 4>; ports disp_out: endpoint remote-endpoint = <&hdmi_in>; ; ; ;
Example (display vsync):
// In gx_i2c_xfer(), add recovery if (status & I2C_STAT_BUS_BUSY) gx_i2c_reset(adap); mdelay(1); gx chip driver
VPU_REG_DEC_CTRL (0xF100_0000) VPU_REG_STATUS (0xF100_0004) // bit 0 = busy VPU_REG_DATA (0xF100_0008) // firmware mailbox Driver requests gx_vpu_fw.bin from /lib/firmware . Missing firmware → VPU fails to start. Missing firmware → VPU fails to start
struct gx_mem_region phys_addr_t start; size_t size; void *cookie; struct list_head list; ; // Allocation from reserved CMA pool void *gx_mem_alloc(size_t size, u32 align); void gx_mem_free(void *handle); struct list_head list
gx_disp: failed to set mode → EDID read failed. Force mode via kernel param: video=HDMI-A-1:1920x1080@60 .
Manually gate unused clocks via /sys/kernel/debug/clk/clk_summary and write to clk_disable .
