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

[Andrey Grodzovsky]

We actually do, while currently it's on hold since I switched to working 
on surprise insertion
for some time it still would be helpful if you could give it a try.

https://cgit.freedesktop.org/~agrodzov/linux/log/?h=drm-misc-next

Andrey

On 2021-03-15 11:01 p.m., Nicholas Johnson wrote:
> On Mon, Mar 15, 2021 at 11:05:21AM -0400, Alex Deucher wrote:
>> 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.
> Sorry, it's been a while; I forgot "-s". And I like your patch much
> better. I look forward to the day when all new PCIe devices only have
> 64-bit MMIO_PREF BARs.
>
> Thanks for looking at this! If you are still doing work on surprise
> removal / driver unloading for Thunderbolt, then I am happy to do
> testing for you. Removal of DRM devices in Linux is the main sore point
> for me, and I would love to see it through.
>
> Regards,
> Nicholas Johnson
>> 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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