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

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Date:   Tue, 1 Sep 2020 12:30:25 -0400
From:   Alex Deucher <alexdeucher@...il.com>
To:     Kai-Heng Feng <kai.heng.feng@...onical.com>
Cc:     "Deucher, Alexander" <alexander.deucher@....com>,
        Christian Koenig <christian.koenig@....com>,
        David Airlie <airlied@...ux.ie>,
        open list <linux-kernel@...r.kernel.org>,
        "open list:DRM DRIVERS" <dri-devel@...ts.freedesktop.org>,
        "open list:RADEON and AMDGPU DRM DRIVERS" 
        <amd-gfx@...ts.freedesktop.org>
Subject: Re: [PATCH] drm/radeon: Reset ASIC if suspend is not managed by
 platform firmware

On Tue, Sep 1, 2020 at 12:21 PM Kai-Heng Feng
<kai.heng.feng@...onical.com> wrote:
>
>
>
> > On Sep 1, 2020, at 22:19, Alex Deucher <alexdeucher@...il.com> wrote:
> >
> > On Tue, Sep 1, 2020 at 3:32 AM Kai-Heng Feng
> > <kai.heng.feng@...onical.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?

Alex

>
> Kai-Heng
>
> >
> > Alex
> >
> >>
> >> [1] https://patchwork.freedesktop.org/patch/335839/
> >>
> >> Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.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
> >>
> >> _______________________________________________
> >> dri-devel mailing list
> >> dri-devel@...ts.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/dri-devel
>

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