Resizable BAR support is missing

#1

After attempt to make Intel ARC work, Orion boots with it (requires mainline kernel and a patch from https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/1824), but xe compains about resizable bar support:

[    2.908081] xe 0000:c3:00.0: [drm] Failed to resize BAR2 to 8192M (-ENOSPC). Consider enabling 'Resizable BAR' support in your BIOS

I wonder if that is a limitation of the platform or that is something that will be fixed in future versions of firmware?

P.S. And meanwhile I’ll switch back to Rx 5700 which doesn’t require ReBAR to be usable.

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#2

From what I understand, resizable BAR is just a software thing and can be enabled, maybe search Discord?

#3

You can do that on DT, but not on ACPI, at least not easily. So vendor of the board must do some homework to provide a toggle.

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#4

Indeed; see a discussion over Resizable BAR on the Pi 5 (using Device Tree): https://github.com/raspberrypi/linux/issues/6621

Though even if it is addressed in ACPI, I wonder if Intel’s drivers will be able to use it correctly on Arm—as it should already be working on the Pi with DT, but it is not.

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#5

Anyway, ACPI must be fixed first. Until then there is no point trying.

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