<html> <head> <base href="https://bugs.freedesktop.org/"> </head> <body> <div> <a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED NOTOURBUG - RX 580 as eGPU amdgpu: gpu post error!" href="https://bugs.freedesktop.org/show_bug.cgi?id=108521#c49">Comment # 49</a> on <a class="bz_bug_link bz_status_RESOLVED bz_closed" title="RESOLVED NOTOURBUG - RX 580 as eGPU amdgpu: gpu post error!" href="https://bugs.freedesktop.org/show_bug.cgi?id=108521">bug 108521</a> from <a class="email" href="mailto:alexdeucher@gmail.com" title="Alex Deucher <alexdeucher@gmail.com>"> Alex Deucher</a> <pre>(In reply to Dimitar Atanasov from <a href="show_bug.cgi?id=108521#c48">comment #48</a>) > May be problem is the CPU, because it has only 16 PCIe lains, so 8 for vega > M, > 4 for NVME, and 4 for others, I have seen that card reader is also connected > on PCIe. It's the MMIO space in the CPU's address space. The CPU (by way of the sbios) defines a window of address space that is used for device MMIO. By default most platforms put a relatively small MMIO windows below 4GB for 32 bit OS compatibility. Having a small MMIO windows limits the amount of space for devices and if there is not enough space some device resources can't be mapped which is what causes the problem. There is often a feature in the sbios config called ">4GB MMIO" or similar which enables a bigger MMIO windows. Some sbioses also enable it dynamically depending on what OS is booted or conditions in the system at boot time (legacy vs UEFI boot). IIRC, it's a requirement for windows 10, so there is probably something about the windows 10 OEM install which causes it to boot with a larger MMIO window set up.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the assignee for the bug.</li> </ul> </body> </html>