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

From: Andrey Grodzovsky
Date: Tue Mar 16 2021 - 10:37:48 EST


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@xxxxxxxxxxxxxx> 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

_______________________________________________
amd-gfx mailing list
amd-gfx@xxxxxxxxxxxxxxxxxxxxx
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&amp;data=04%7C01%7Candrey.grodzovsky%40amd.com%7Cbbb3dd71d833433cc92b08d8e8537709%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637514792478220135%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=LBx9fok9E7hD8AKWm9kqFVjhsxsvnLKifDX18MR3eC4%3D&amp;reserved=0
_______________________________________________
amd-gfx mailing list
amd-gfx@xxxxxxxxxxxxxxxxxxxxx
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.freedesktop.org%2Fmailman%2Flistinfo%2Famd-gfx&amp;data=04%7C01%7Candrey.grodzovsky%40amd.com%7Cbbb3dd71d833433cc92b08d8e8537709%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637514792478230124%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&amp;sdata=3uh0ATLmWUeuYF6b0GZ64b5sKvzyWk2p0v8LjXJf9Ww%3D&amp;reserved=0