[PATCH] drm/radeon: Reset ASIC if suspend is not managed by platform firmware

[Alex Deucher]

On Tue, Sep 1, 2020 at 3:32 AM Kai-Heng Feng
<kai.heng.feng at canonical.com> wrote:
>
> Suspend with s2idle or by the following steps cause screen frozen:
>  # echo devices > /sys/power/pm_test
>  # echo freeze > /sys/power/mem
>
> [  289.625461] [drm:uvd_v1_0_ib_test [radeon]] *ERROR* radeon: fence wait timed out.
> [  289.625494] [drm:radeon_ib_ring_tests [radeon]] *ERROR* radeon: failed testing IB on ring 5 (-110).
>
> The issue doesn't happen on traditional S3, probably because firmware or
> hardware provides extra power management.
>
> Inspired by Daniel Drake's patch [1] on amdgpu, using a similar approach
> can fix the issue.

It doesn't actually fix the issue.  The device is never powered down
so you are using more power than you would if you did not suspend in
the first place.  The reset just works around the fact that the device
is never powered down.

Alex

>
> [1] https://patchwork.freedesktop.org/patch/335839/
>
> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
> ---
>  drivers/gpu/drm/radeon/radeon_device.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/radeon/radeon_device.c b/drivers/gpu/drm/radeon/radeon_device.c
> index 266e3cbbd09b..df823b9ad79f 100644
> --- a/drivers/gpu/drm/radeon/radeon_device.c
> +++ b/drivers/gpu/drm/radeon/radeon_device.c
> @@ -33,6 +33,7 @@
>  #include <linux/slab.h>
>  #include <linux/vga_switcheroo.h>
>  #include <linux/vgaarb.h>
> +#include <linux/suspend.h>
>
>  #include <drm/drm_cache.h>
>  #include <drm/drm_crtc_helper.h>
> @@ -1643,6 +1644,8 @@ int radeon_suspend_kms(struct drm_device *dev, bool suspend,
>                 rdev->asic->asic_reset(rdev, true);
>                 pci_restore_state(dev->pdev);
>         } else if (suspend) {
> +               if (pm_suspend_no_platform())
> +                       rdev->asic->asic_reset(rdev, true);
>                 /* Shut down the device */
>                 pci_disable_device(dev->pdev);
>                 pci_set_power_state(dev->pdev, PCI_D3hot);
> --
> 2.17.1
>
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