[PATCH 1/1] amdgpu: use MMIO to init atombios if device is Thunderbolt / USB4 attached

[Alex Deucher]

On Mon, Mar 15, 2021 at 4:04 AM Nicholas Johnson
<nicholas.johnson-opensource at outlook.com.au> wrote:
>
> When using some Thunderbolt hosts using BIOS-assisted PCI enumeration
> with IO BAR assigned, we get an atombios timeout, such as:
>
> [drm:atom_op_jump [amdgpu]] *ERROR* atombios stuck in loop for more than 20secs aborting
> [drm:amdgpu_atom_execute_table_locked [amdgpu]] *ERROR* atombios stuck executing B456 (len 304, WS 4, PS 0) @ 0xB51B
> [drm:amdgpu_atom_execute_table_locked [amdgpu]] *ERROR* atombios stuck executing B104 (len 183, WS 0, PS 8) @ 0xB17E
> amdgpu 0000:08:00.0: amdgpu: gpu post error!
> amdgpu 0000:08:00.0: amdgpu: Fatal error during GPU init
> amdgpu: probe of 0000:08:00.0 failed with error -22
>
> A workaround is to use MMIO to access ATOMBIOS when device is
> Thunderbolt / USB4 attached.

Missing your signed-off-by.  Also, we can just remove the legacy IO
callbacks altogether.  They are leftover from radeon and not required
at all on amdgpu.

Alex


> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
> index 86add0f4e..5d16ec10d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_atombios.c
> @@ -1999,11 +1999,15 @@ int amdgpu_atombios_init(struct amdgpu_device *adev)
>         atom_card_info->reg_read = cail_reg_read;
>         atom_card_info->reg_write = cail_reg_write;
>         /* needed for iio ops */
> -       if (adev->rio_mem) {
> +       if (adev->rio_mem && !pci_is_thunderbolt_attached(adev->pdev)) {
>                 atom_card_info->ioreg_read = cail_ioreg_read;
>                 atom_card_info->ioreg_write = cail_ioreg_write;
>         } else {
> -               DRM_DEBUG("PCI I/O BAR is not found. Using MMIO to access ATOM BIOS\n");
> +               if (pci_is_thunderbolt_attached(adev->pdev))
> +                       DRM_DEBUG("Device is attached via Thunderbolt / USB4. Using MMIO to access ATOM BIOS\n");
> +               else
> +                       DRM_DEBUG("PCI I/O BAR is not found. Using MMIO to access ATOM BIOS\n");
> +
>                 atom_card_info->ioreg_read = cail_reg_read;
>                 atom_card_info->ioreg_write = cail_reg_write;
>         }
> --
> 2.30.2
>
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