ac100: uvcvideo devices don't work with grate-driver

[emulti]

After installing the grate-driver libdrm, opentegra, mesa and libvdpau I noticed that the uvcvideo webcam device on AC100 no longer works. This was functional with stock mesa/libdrm/modesetting on 5.7.8.

tested with xawtv and guvcview, see attached logs. guvcview gives a little more information in the error message.

Also, the uvcvideo driver loads with some 'entity was not initialized' errors on the linux-grate kernel. On upstream 5.7.8 it loads OK.

Please see attached log. uvcvideo.txt

[kusma]

This doesn't sound related to mesa at all, as that is a user space driver.

[emulti]

uvcvideo is a kernel module- the error message refers to Mesa & grate driver. Apologies if I have misplaced the report.

[digetx]

@kusma The log contains:

Mesa 19.3.1 implementation error: Failed to link fixed function fragment shader: error: Too many fragment shader default uniform block components

../src/gallium/drivers/grate/fp/tgsi.c:161:emit_tgsi_instr: Assertion `!"unsupported TGSI-opcode!"' failed.

@emulti Please add LIBGL_ALWAYS_SOFTWARE=1 to environment variables.