Comment 62 for bug 1747463

Hi,
  I still encounter a same issue concerned to ext4 fs corruption using linux kernels 4.19.16... 4.20.27 on HP laptop 17-ak041ur (2 pcs on hand).

  Laptop configs are A6-9220 radeon r4 5 compute cores 2c+3g, 4G RAM, 200GB Intel SSD (1st laptop) or 500GB Toshiba HDD (2nd laptop)
I'm using OS ALT linux distribution (www.altlinux.org)
  Boot and installation of the system is performed flawlessly using LiveCD if LAN cable is NOT attached. dmesg shows plenty of "AMD-Vi: Completion-Wait loop timed out" errors.
  Connecting LAN cable during LiveCD boot results graphical target boot failure or kernel panic.
  After first reboot the system won't boot anyway and ext4 filesystem corruption occurs.

 As investigtion revealed that switching IOMMU off (amd_iommu=off and/or iommu=soft) solves the issue. "amd_iommu=fullflush" doesn't work for me.

I've discovered several patches concerning solution of (amd_)iommu issues in linux-kernel mailing list archive, but they are either applied to kernels mentioned above already or their application doesn't solve the issue for me.
Above mentioned patch (https://patchwork.freedesktop.org/patch/157327/) is not applicable to mentioned kernel versions any more.
  Therefore my question is: am I missing some patch that already solved the issue or should I provide more specific bug report?