Romain Tisserand
Using KMS/DRM driver from WIP SDL2.0.6 on Linux/ARM SoC RockChip RK3328 (ARM Mali 450 MP2 GPU).
The current code is using GBM_BO_FORMAT_XRGB8888 as GBM buffer format specifier.
The Mali driver (it has been confirmed some other vendor implementations too) expects GBM_FORMAT_XRGB8888.
The Mesa implementation is actually handling both values as the same, but it's not implemented like this into every gbm.h vendor header.
https://github.com/ideak/mesa/blob/master/src/gbm/backends/dri/gbm_dri.c
So with stock SDL2 on my card (Mali vendor implementation), it does not work, eglCreateWindowSurface fails, and gbm_is_format_supported fails too (with the BO variant).
It runs fine with GBM_FORMAT_XRGB8888.
Here is a link of the gbm.h from Mali user-space driver :
https://github.com/rockchip-linux/libmali/blob/rockchip/include/gbm.h