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

[Kai-Heng Feng]

> 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?

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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