Cannot allocate more than 256MB in one allocation on my discrete Intel GPU using SYCL/DPC++ on Linux

Question

When trying to allocate more than 256MB in one allocation on a discrete Intel GPU using SYCL/DPC++ on Linux, I get a runtime error and the program exits immediately, despite having significantly more than 256MB of free space left on the device.

Answer 1

You most likely don't have ReBAR enabled for your dGPU. Intel GPUs were designed with having enabled ReBAR, so without it the behavior may be unexpected.

If your motherboard and CPU support ReBAR, you should be able to enable it in the BIOS. For more (Intel specific) details, see also here.