Re: [PATCH] accel/ivpu: Don't enter d0i3 during FLR

[Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx>]

On 10/17/2023 2:43 AM, Stanislaw Gruszka wrote:
> On Fri, Oct 06, 2023 at 09:25:29AM -0600, Jeffrey Hugo wrote:
> > On 10/3/2023 12:42 AM, Stanislaw Gruszka wrote:
> > > From: Jacek Lawrynowicz <jacek.lawrynowicz@xxxxxxxxxxxxxxx>
> > >
> > > Fix a bug on some platforms where FLR causes complete system
> > > hang when CPU is low power states (C8 or above).
> >
> > Why does FLR cause a complete system hang?
>
> This HW bug is still under debug and it is not yet root caused.

Ouch.  Good luck with that.

> > Why does avoiding d0i3 fix the
> > issue?  Feels like there could be a lot more detail here.
>
> We only know that we should avoid entering D0i3.
>
> I will change the log this way:
>
> Avoid HW bug on some platforms where we enter D0i3 state
> and CPU is in low power states (C8 or above).
>
> Regards
> Stanislaw
>
> > > Fixes: 852be13f3bd3 ("accel/ivpu: Add PM support")
> > > Cc: stable@xxxxxxxxxxxxxxx
> > > Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@xxxxxxxxxxxxxxx>
> > > Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@xxxxxxxxxxxxxxx>
> > > Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@xxxxxxxxxxxxxxx>
> > > ---
> > >    drivers/accel/ivpu/ivpu_drv.c     | 11 ++++++++---
> > >    drivers/accel/ivpu/ivpu_drv.h     |  1 +
> > >    drivers/accel/ivpu/ivpu_hw.h      |  8 ++++++++
> > >    drivers/accel/ivpu/ivpu_hw_37xx.c |  1 +
> > >    drivers/accel/ivpu/ivpu_hw_40xx.c |  1 +
> > >    drivers/accel/ivpu/ivpu_pm.c      |  3 ++-
> > >    6 files changed, 21 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/accel/ivpu/ivpu_drv.c b/drivers/accel/ivpu/ivpu_drv.c
> > > index 3f4efa07ce7c..1eb232e903e8 100644
> > > --- a/drivers/accel/ivpu/ivpu_drv.c
> > > +++ b/drivers/accel/ivpu/ivpu_drv.c
> > > @@ -367,14 +367,19 @@ int ivpu_boot(struct ivpu_device *vdev)
> > >    	return 0;
> > >    }
> > > -int ivpu_shutdown(struct ivpu_device *vdev)
> > > +void ivpu_prepare_for_reset(struct ivpu_device *vdev)
> > >    {
> > > -	int ret;
> > > -
> > >    	ivpu_hw_irq_disable(vdev);
> > >    	disable_irq(vdev->irq);
> > >    	ivpu_ipc_disable(vdev);
> > >    	ivpu_mmu_disable(vdev);
> > > +}
> > > +
> > > +int ivpu_shutdown(struct ivpu_device *vdev)
> > > +{
> > > +	int ret;
> > > +
> > > +	ivpu_prepare_for_reset(vdev);
> > >    	ret = ivpu_hw_power_down(vdev);
> > >    	if (ret)
> > > diff --git a/drivers/accel/ivpu/ivpu_drv.h b/drivers/accel/ivpu/ivpu_drv.h
> > > index 98380c1db9fa..a3b45032e6cf 100644
> > > --- a/drivers/accel/ivpu/ivpu_drv.h
> > > +++ b/drivers/accel/ivpu/ivpu_drv.h
> > > @@ -158,6 +158,7 @@ void ivpu_file_priv_put(struct ivpu_file_priv **link);
> > >    int ivpu_boot(struct ivpu_device *vdev);
> > >    int ivpu_shutdown(struct ivpu_device *vdev);
> > > +void ivpu_prepare_for_reset(struct ivpu_device *vdev);
> > >    static inline u8 ivpu_revision(struct ivpu_device *vdev)
> > >    {
> > > diff --git a/drivers/accel/ivpu/ivpu_hw.h b/drivers/accel/ivpu/ivpu_hw.h
> > > index ab341237bcf9..1079e06255ba 100644
> > > --- a/drivers/accel/ivpu/ivpu_hw.h
> > > +++ b/drivers/accel/ivpu/ivpu_hw.h
> > > @@ -13,6 +13,7 @@ struct ivpu_hw_ops {
> > >    	int (*power_up)(struct ivpu_device *vdev);
> > >    	int (*boot_fw)(struct ivpu_device *vdev);
> > >    	int (*power_down)(struct ivpu_device *vdev);
> > > +	int (*reset)(struct ivpu_device *vdev);
> > >    	bool (*is_idle)(struct ivpu_device *vdev);
> > >    	void (*wdt_disable)(struct ivpu_device *vdev);
> > >    	void (*diagnose_failure)(struct ivpu_device *vdev);
> > > @@ -91,6 +92,13 @@ static inline int ivpu_hw_power_down(struct ivpu_device *vdev)
> > >    	return vdev->hw->ops->power_down(vdev);
> > >    };
> > > +static inline int ivpu_hw_reset(struct ivpu_device *vdev)
> > > +{
> > > +	ivpu_dbg(vdev, PM, "HW reset\n");
> > > +
> > > +	return vdev->hw->ops->reset(vdev);
> > > +};
> > > +
> > >    static inline void ivpu_hw_wdt_disable(struct ivpu_device *vdev)
> > >    {
> > >    	vdev->hw->ops->wdt_disable(vdev);
> > > diff --git a/drivers/accel/ivpu/ivpu_hw_37xx.c b/drivers/accel/ivpu/ivpu_hw_37xx.c
> > > index edd4d860f135..1e842739e937 100644
> > > --- a/drivers/accel/ivpu/ivpu_hw_37xx.c
> > > +++ b/drivers/accel/ivpu/ivpu_hw_37xx.c
> > > @@ -1036,6 +1036,7 @@ const struct ivpu_hw_ops ivpu_hw_37xx_ops = {
> > >    	.power_up = ivpu_hw_37xx_power_up,
> > >    	.is_idle = ivpu_hw_37xx_is_idle,
> > >    	.power_down = ivpu_hw_37xx_power_down,
> > > +	.reset = ivpu_hw_37xx_reset,
> > >    	.boot_fw = ivpu_hw_37xx_boot_fw,
> > >    	.wdt_disable = ivpu_hw_37xx_wdt_disable,
> > >    	.diagnose_failure = ivpu_hw_37xx_diagnose_failure,
> > > diff --git a/drivers/accel/ivpu/ivpu_hw_40xx.c b/drivers/accel/ivpu/ivpu_hw_40xx.c
> > > index a48cd36f9931..d7b8ec0410af 100644
> > > --- a/drivers/accel/ivpu/ivpu_hw_40xx.c
> > > +++ b/drivers/accel/ivpu/ivpu_hw_40xx.c
> > > @@ -1186,6 +1186,7 @@ const struct ivpu_hw_ops ivpu_hw_40xx_ops = {
> > >    	.power_up = ivpu_hw_40xx_power_up,
> > >    	.is_idle = ivpu_hw_40xx_is_idle,
> > >    	.power_down = ivpu_hw_40xx_power_down,
> > > +	.reset = ivpu_hw_40xx_reset,
> > >    	.boot_fw = ivpu_hw_40xx_boot_fw,
> > >    	.wdt_disable = ivpu_hw_40xx_wdt_disable,
> > >    	.diagnose_failure = ivpu_hw_40xx_diagnose_failure,
> > > diff --git a/drivers/accel/ivpu/ivpu_pm.c b/drivers/accel/ivpu/ivpu_pm.c
> > > index 28a0d1111e12..da46f95b008a 100644
> > > --- a/drivers/accel/ivpu/ivpu_pm.c
> > > +++ b/drivers/accel/ivpu/ivpu_pm.c
> > > @@ -261,7 +261,8 @@ void ivpu_pm_reset_prepare_cb(struct pci_dev *pdev)
> > >    	ivpu_dbg(vdev, PM, "Pre-reset..\n");
> > >    	atomic_inc(&vdev->pm->reset_counter);
> > >    	atomic_set(&vdev->pm->in_reset, 1);
> > > -	ivpu_shutdown(vdev);
> > > +	ivpu_prepare_for_reset(vdev);
> > > +	ivpu_hw_reset(vdev);
> > >    	ivpu_pm_prepare_cold_boot(vdev);
> > >    	ivpu_jobs_abort_all(vdev);
> > >    	ivpu_dbg(vdev, PM, "Pre-reset done.\n");