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drm/amdgpu: do not use passthrough mode in Xen dom0

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commit 19965d8259fdabc6806da92adda49684f5bcbec5 upstream.

While technically Xen dom0 is a virtual machine too, it does have
access to most of the hardware so it doesn't need to be considered a
"passthrough". Commit b818a5d37454 ("drm/amdgpu/gmc: use PCI BARs for
APUs in passthrough") changed how FB is accessed based on passthrough
mode. This breaks amdgpu in Xen dom0 with message like this:

    [drm:dc_dmub_srv_wait_idle [amdgpu]] *ERROR* Error waiting for DMUB idle: status=3

While the reason for this failure is unclear, the passthrough mode is
not really necessary in Xen dom0 anyway. So, to unbreak booting affected
kernels, disable passthrough mode in this case.

Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1985
Fixes: b818a5d37454 ("drm/amdgpu/gmc: use PCI BARs for APUs in passthrough")
Signed-off-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Marek Marczykowski-Górecki 2022-04-27 01:57:15 +02:00 committed by Greg Kroah-Hartman
parent c10bab89a1
commit 1a78d8fe66
1 changed files with 3 additions and 1 deletions
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4
drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
View File

@ -24,6 +24,7 @@
#include <linux/module.h>
#include <drm/drm_drv.h>
#include <xen/xen.h>
#include "amdgpu.h"
#include "amdgpu_ras.h"
@ -694,7 +695,8 @@ void amdgpu_detect_virtualization(struct amdgpu_device *adev)
adev->virt.caps |= AMDGPU_SRIOV_CAPS_ENABLE_IOV;
if (!reg) {
if (is_virtual_machine()) /* passthrough mode exclus sriov mod */
/* passthrough mode exclus sriov mod */
if (is_virtual_machine() && !xen_initial_domain())
adev->virt.caps |= AMDGPU_PASSTHROUGH_MODE;
}