[PATCH] drm/amdgpu/sriov: omit fbcon error under sriov or passthrough

[Deng, Emily]

Hi Christian,
Do you think this is because the wrong use case? Even we add the error log, the issue still happens. Could we change this error to warning? As for the right method to remove the driver, it shouldn’t occur issues.

Best wishes
Emily Deng
From: Koenig, Christian <Christian.Koenig at amd.com>
Sent: Wednesday, September 18, 2019 5:45 PM
To: Deng, Emily <Emily.Deng at amd.com>
Cc: Zhang, Jack (Jian) <Jack.Zhang1 at amd.com>; amd-gfx at lists.freedesktop.org; Teng, Rui <Rui.Teng at amd.com>; Cui, Flora <Flora.Cui at amd.com>
Subject: RE: [PATCH] drm/amdgpu/sriov: omit fbcon error under sriov or passthrough

Yes, exactly.

The problem is that even when output is qxl or the Intel driver our driver is still loaded and forcefully removing it renders the desktop unusable.

Christian.


Am 18.09.2019 11:24 schrieb "Deng, Emily" <Emily.Deng at amd.com<mailto:Emily.Deng at amd.com>>:

Hi Christian,

Do you mean, for passthrough mode, the desktop is rendered by our asic, but enduser is trying to remove the driver by hot plug?



Best wishes

Emily Deng

From: Koenig, Christian <Christian.Koenig at amd.com<mailto:Christian.Koenig at amd.com>>
Sent: Wednesday, September 18, 2019 4:44 PM
To: Deng, Emily <Emily.Deng at amd.com<mailto:Emily.Deng at amd.com>>
Cc: Zhang, Jack (Jian) <Jack.Zhang1 at amd.com<mailto:Jack.Zhang1 at amd.com>>; amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>; Teng, Rui <Rui.Teng at amd.com<mailto:Rui.Teng at amd.com>>; Cui, Flora <Flora.Cui at amd.com<mailto:Flora.Cui at amd.com>>
Subject: RE: [PATCH] drm/amdgpu/sriov: omit fbcon error under sriov or passthrough



Hi Emily,



Yeah, exactly that's the problem: In some cases the driver can be unloaded while it is still in use!



See we added this error message because endusers tried to use PCIe hot plug to unload the driver to use the hardware for paththrough.



But this will completely nuke your desktop, even when amdgpu is only a secondary device like in the qxl case.



Jack is using the correct way of doing it, e.g. using "modprobe -r" or rmmod. Both commands check the use count before unloading the driver instances.



I don't see a way to distingt the two cases and what Jack is doing is unfortunate not the common one.



Regards,

Christian.





Am 18.09.2019 10:08 schrieb "Deng, Emily" <Emily.Deng at amd.com<mailto:Emily.Deng at amd.com>>:

Hi Christian,

     Before unloading driver, user must sure there is not any userspace to use of amdgpu, if not, it will report driver is in use. And the unloading driver is a feature about amdgpu driver which will be easier to replace driver without rebooting VM. Do you think it has any issue about driver unloading path?



Best wishes

Emily Deng

From: Koenig, Christian <Christian.Koenig at amd.com<mailto:Christian.Koenig at amd.com>>
Sent: Wednesday, September 18, 2019 3:54 PM
To: Zhang, Jack (Jian) <Jack.Zhang1 at amd.com<mailto:Jack.Zhang1 at amd.com>>
Cc: amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>; Teng, Rui <Rui.Teng at amd.com<mailto:Rui.Teng at amd.com>>; Deng, Emily <Emily.Deng at amd.com<mailto:Emily.Deng at amd.com>>; Cui, Flora <Flora.Cui at amd.com<mailto:Flora.Cui at amd.com>>
Subject: RE: [PATCH] drm/amdgpu/sriov: omit fbcon error under sriov or passthrough



Hi Jack,



Well that believe is unfortunately completely wrong.



The point is that ANY use of amdgpu by userspace will prevent correct driver unload, that qxl is used for the fbcon doesn't change anything here.



So the patch is a clear NAK. Driver unload is not supposed to work even under SRIOV.



Regards,

Christian.







Am 18.09.2019 09:32 schrieb "Zhang, Jack (Jian)" <Jack.Zhang1 at amd.com<mailto:Jack.Zhang1 at amd.com>>:

Hi, Christian and folks,

In virtual machines(such virt-manager), there's always a virtual graphics device existed like "qxl" as the default gfx device.
So under such condition, we believe it's reasonable to unload amdgpu driver as it is not treated as the default fbcon device.

Would you please help to review this patch?

Best wishes,
Jack

-----Original Message-----
From: Jack Zhang <Jack.Zhang1 at amd.com<mailto:Jack.Zhang1 at amd.com>>
Sent: Wednesday, September 18, 2019 3:25 PM
To: amd-gfx at lists.freedesktop.org<mailto:amd-gfx at lists.freedesktop.org>
Cc: Zhang, Jack (Jian) <Jack.Zhang1 at amd.com<mailto:Jack.Zhang1 at amd.com>>
Subject: [PATCH] drm/amdgpu/sriov: omit fbcon error under sriov or passthrough

In virtual machine, there would be a qxl or cirrus graphics device as the default master fbcon device.

So for PF(passthrough mode) or SRIOV VF, it is reasonable to unload amdgpu driver. Amdgpu doesn't have to be the only fbcon device under this condition.

Signed-off-by: Jack Zhang <Jack.Zhang1 at amd.com<mailto:Jack.Zhang1 at amd.com>>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 420888e..ada2b25 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -1103,8 +1103,9 @@ static void
 amdgpu_pci_remove(struct pci_dev *pdev)  {
         struct drm_device *dev = pci_get_drvdata(pdev);
-
-       DRM_ERROR("Device removal is currently not supported outside of fbcon\n");
+       struct amdgpu_device *adev = dev->dev_private;
+       if (!amdgpu_sriov_vf(adev) && !amdgpu_passthrough(adev))
+               DRM_ERROR("Device removal is currently not supported outside of
+fbcon\n");
         drm_dev_unplug(dev);
         drm_dev_put(dev);
         pci_disable_device(pdev);
--
2.7.4



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