DRM framebuffer capture tool

[#1]

On behalf of Gopise Yuan.

This is an update for the DRM framebuffer capture tool I used to share with the team. Some enhancement added.

Might be useful for debugging some display related issues.

Some special notes:

1. Behavior of DRM subsystem is different between L4.x and L5.x.

For L4.x, you can capture the RGB buffer without any problem. But, there’s no API for YUV (multi-plane) buffer. To capture YUV, need to apply “kernel_0001-drm-Add-getfb2-ioctl_L4.14.98.patch”.

For L5.x, mapping/capturing the internal buffer is not allowed by default due to security reason. A simple change in “0001-drm-enable-mapping-of-internal-object-for-debugging_L5.x.patch” can disable this guard.

2. Capture raw data only. RGB and YUV (packed/planar, 420/422) supported.
3. Support de-tile on “Amphion tile” (VPU, NV12 only) and “Super tile” (Vivante GPU). Please use “-t” to enable this. Other tile might not be supported.
4. This is a static linked binary. You can run it on any ARM64 based Linux/Android system in theory (prerequisites in item #1). If you need source code, come to me.

To get more details on how to use it, use “-?” option:

DRM screen capture

DRM based screen capture program

Usage:

    ./drmfbcap [OP] [ARG]

[OP] OPeration (optional):

    -v Show version.

    -? Show help information.

    -i Show information about target DRM device only (no capture).

    -t Perform de-tile for tile format.

    -d DRM device to open. [ARG] should contain the path to the device node. Default: '/dev/dri/card0'

    -o Output folder. [ARG] should contain the path to the output folder. Default: '.'

    -p Specific plane # to capture. [ARG] should contain the plane number. If no '-p' specified, capture all planes

Example:

    ./drmfbcap

  Capture all planes on default DRM device.

    ./drmfbcap -d /dev/dri/controlD64

  Capture all planes on '/dev/dri/controlD64' device.

    ./drmfbcap -p 44 -t -o /sdcard

  Capture plane 44, do de-tile after capture and then output to /sdcard/.

Raw buffer capture will be done for each enabled/target plane and one file for each.

Captured file will be saved to './' if not specified.

--- By Gopise, 2022/08

Updated_2023_10_16:

continuous capture (repeat mode) support with this link:

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/DRM-screen-capture-tool/ta-p/1725363