FBIOGET_FSCREENINFO
Applicability
Product |
Supported |
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√ |
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Description
Obtains fixed FB information, including the display buffer address in user mode and display buffer size.
Prototype
int ioctl (int fd, FBIOGET_FSCREENINFO, fb_fix_screeninfo *fix)
Parameters
Parameter |
Input/Output |
Description |
|---|---|---|
fd |
Input |
File descriptor of an FB device. When open("/dev/fbx") is called in the application, the file descriptor of the FB device corresponding to the current VO device is returned. |
FBIOGET_FSCREENINFO |
Input |
ioctl number. |
fix |
Output |
Pointer to the fixed information structure. |
Returns
- 0: success
- Other values: failure
Restrictions
- Before using the HiFB API, you need to call hi_mpi_vo_enable to enable the VO device.
- The display buffer obtains the user-mode virtual address using the mmap function of the kernel. Note that the user-mode virtual address cannot be accessed by the accelerator. To set the user-mode address for the accelerator, use the mmio_start parameter in fb_fix_screeninfo.
- If a graphics layer does not need to be displayed, you need to call the munmap API of the kernel to release the user-mode virtual address. Otherwise, the graphics layer is unavailable and the driver cannot exit.
- This API does not support multiple processes or multiple threads.
Parent topic: HiFB for Managing Overlaid Graphics Layers