gbm_gralloc fails gralloctest gralloc_order

[maurossi]

Hello,
gbm_gralloc is the only gralloc0 implementation not passing gralloc_order test,
the test case is described in the comment

gralloctest.c has not changed much, here is a recent version

https://android.googlesource.com/platform/external/minigbm/+/refs/tags/android-11.0.0_r33/cros_gralloc/gralloc0/tests/gralloctest.c

@line 394
	/*
	 * Duplicate the buffer handle to simulate an additional reference
	 * in same process.
	 */
	native_handle_t *native_handle = duplicate_buffer_handle(info.handle);
	duplicate.handle = native_handle;

	CHECK(unregister_buffer(ctx->module, &duplicate) == 0);
	CHECK(register_buffer(ctx->module, &duplicate));    /* @line 402 here is the CHECK that is failing only with gbm_gralloc */

[rsglobal]

Hi,

Minigbm's private handle structure has unique ID field, which is used to distinguish between duplicated/unique registration.
gbm_gralloc does not have such field.

But recently I was searching for unified way to get dma-buf unique fingerprint, and it seems that fstat(fd[0]) -> st_ino should be true unique number per dma-buf and can be used here.