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

[Kai-Heng Feng]

> On Sep 2, 2020, at 00:30, Alex Deucher <alexdeucher at gmail.com> wrote:
> 
> On Tue, Sep 1, 2020 at 12:21 PM Kai-Heng Feng
> <kai.heng.feng at canonical.com> wrote:
>> 
>> 
>> 
>>> On Sep 1, 2020, at 22:19, Alex Deucher <alexdeucher at gmail.com> wrote:
>>> 
>>> 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.
>> 
>> So how do we properly suspend/resume the device without help from platform firmware?
> 
> I guess you don't?

Unfortunate but I guess we need to accept reality and use the default suspend method.

Kai-Heng

> 
> Alex
> 
> 
>> 
>> Kai-Heng
>> 
>>> 
>>> 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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>>