RE: [EXTERNAL] Re: amdgpu error whenever IOMMU is enabled

["Merger, Edgar [AUTOSOL/MAS/AUGS]" <Edgar.Merger@emerson.com>]

Alright, so is this going to make it into an upstream-Kernel?

-----Original Message-----
From: jroedel@suse.de <jroedel@suse.de> 
Sent: Freitag, 6. November 2020 15:06
To: Merger, Edgar [AUTOSOL/MAS/AUGS] <Edgar.Merger@emerson.com>
Cc: iommu@lists.linux-foundation.org
Subject: Re: [EXTERNAL] Re: amdgpu error whenever IOMMU is enabled

On Fri, Nov 06, 2020 at 01:03:22PM +0000, Merger, Edgar [AUTOSOL/MAS/AUGS] wrote:
> Thank you. I do think that this is the GPU. Would you please elaborate 
> on what that quirk would be?

The GPU seems to have broken ATS, or require driver setup to make ATS work. Anyhow, ATS is unstable for Linux to use, so it must not be enabled.

This diff to the kernel should do that:

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c index f70692ac79c5..3911b0ec57ba 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -5176,6 +5176,8 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x6900, quirk_amd_harvest_no_ats);  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x7312, quirk_amd_harvest_no_ats);
 /* AMD Navi14 dGPU */
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x7340, quirk_amd_harvest_no_ats);
+/* AMD Raven platform iGPU */
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x15d8, 
+quirk_amd_harvest_no_ats);
 #endif /* CONFIG_PCI_ATS */
 
 /* Freescale PCIe doesn't support MSI in RC mode */
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