Comment 5 for bug 1894869

The patch you mention is already included in our QEMU builds, but as you correctly said it's only implemented for T5 devices.

You'd have to go about patching your QEMU yourself if you want this to work, or message the upstream QEMU maintainers to include a fix (or even better: provide them with the fix :) ).

In any case, a full 'lspci -nnkvv' output for your device (and any virtual functions thereof) would help.

I've attached a QEMU patch for you to try, it has "0xNNNN" instead of the actual device ID of your T4, so change that before applying the patch. No liability of this working at all, here be dragons and if it breaks everything you're on your own, but I believe it's simple enough to work, provided the hardware quirk is the same on T4 as on T5.

You can find our QEMU downstream at https://git.proxmox.com/?p=pve-qemu.git;a=summary, if you put it in debian/patches/pve and mention the file in debian/patches/series you should be able to build a pve-qemu against it. Check out our developer documentation (https://pve.proxmox.com/wiki/Developer_Documentation) as well.