RE: [BUG] "Pre-boot DMA Protection" makes AMDGPU stop working

[Deucher, Alexander]

[AMD Public Use]

> -----Original Message-----
> From: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>
> Sent: Thursday, July 2, 2020 8:04 AM
> To: Joerg Roedel <jroedel@xxxxxxx>
> Cc: Deucher, Alexander <Alexander.Deucher@xxxxxxx>;
> iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; open list <linux-kernel@xxxxxxxxxxxxxxx>
> Subject: [BUG] "Pre-boot DMA Protection" makes AMDGPU stop working
> 
> Hi,
> 
> A more detailed bug report can be found at [1].
> 
> I have a AMD Renoir system that can't enter graphical session because there
> are many IOMMU splat.
> 
> Alex suggested to disable "Pre-boot DMA Protection", I can confirm once it's
> disabled, AMDGPU starts working with IOMMU enabled.
> So raise the issue here because I have no knowledge on how to reset the
> IOMMU.

+ Suravee

This is part of MS's Secure Core initiative.  We are investigating how to properly handle this properly on Linux.  Stay tuned.

Alex

> 
> [1]
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitla
> b.freedesktop.org%2Fdrm%2Famd%2F-
> %2Fissues%2F1204&amp;data=02%7C01%7Calexander.deucher%40amd.com
> %7C60746a6fecf04a5e570908d81e8011c6%7C3dd8961fe4884e608e11a82d994
> e183d%7C0%7C0%7C637292882713301680&amp;sdata=r6cj19Vc8N0%2FSmsb
> CAJva%2BabMD2b5r2lvPLIxZSacoY%3D&amp;reserved=0
> 
> Kai-Heng