[PATCH v6 4/7] drm/amd: Capture errors in amdgpu_switcheroo_set_state()

[Alex Deucher]

On Mon, Oct 9, 2023 at 12:52 PM Mario Limonciello
<mario.limonciello at amd.com> wrote:
>
> amdgpu_switcheroo_set_state() calls lots of functions that could
> fail under memory pressure or for other reasons.  Don't assume
> everything can successfully run sequentially, and check return codes
> for everything that returns one.

I think the reason we do this rather than returning errors was not
because we assumed they would be successful, but that it seemed better
to try and restore the hardware than to bail early.

Alex

>
> Acked-by: Christian König <christian.koenig at amd.com>
> Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 36 +++++++++++++++++-----
>  1 file changed, 29 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index 0f98f720d9ca..65a4537ee6f3 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -1749,23 +1749,45 @@ static void amdgpu_switcheroo_set_state(struct pci_dev *pdev,
>                 /* don't suspend or resume card normally */
>                 dev->switch_power_state = DRM_SWITCH_POWER_CHANGING;
>
> -               pci_set_power_state(pdev, PCI_D0);
> -               amdgpu_device_load_pci_state(pdev);
> +               r = pci_set_power_state(pdev, PCI_D0);
> +               if (r) {
> +                       DRM_WARN("pci_set_power_state failed (%d)\n", r);
> +                       return;
> +               }
> +               if (!amdgpu_device_load_pci_state(pdev))
> +                       return;
>                 r = pci_enable_device(pdev);
>                 if (r)
>                         DRM_WARN("pci_enable_device failed (%d)\n", r);
> -               amdgpu_device_resume(dev, true);
> +               r = amdgpu_device_resume(dev, true);
> +               if (r) {
> +                       DRM_WARN("amdgpu_device_resume failed (%d)\n", r);
> +                       return;
> +               }
>
>                 dev->switch_power_state = DRM_SWITCH_POWER_ON;
>         } else {
>                 pr_info("switched off\n");
>                 dev->switch_power_state = DRM_SWITCH_POWER_CHANGING;
> -               amdgpu_device_prepare(dev);
> -               amdgpu_device_suspend(dev, true);
> -               amdgpu_device_cache_pci_state(pdev);
> +               r = amdgpu_device_prepare(dev);
> +               if (r) {
> +                       DRM_WARN("amdgpu_device_prepare failed (%d)\n", r);
> +                       return;
> +               }
> +               r = amdgpu_device_suspend(dev, true);
> +               if (r) {
> +                       DRM_WARN("amdgpu_device_suspend failed (%d)\n", r);
> +                       return;
> +               }
> +               if (!amdgpu_device_cache_pci_state(pdev))
> +                       return;
>                 /* Shut down the device */
>                 pci_disable_device(pdev);
> -               pci_set_power_state(pdev, PCI_D3cold);
> +               r = pci_set_power_state(pdev, PCI_D3cold);
> +               if (r) {
> +                       DRM_WARN("pci_set_power_state failed (%d)\n", r);
> +                       return;
> +               }
>                 dev->switch_power_state = DRM_SWITCH_POWER_OFF;
>         }
>  }
> --
> 2.34.1
>