Re: [PATCH] venus: core: add shutdown callback for venus

[mansur]

Hi Sai,

> On 2020-06-24 12:17, Sai Prakash Ranjan wrote:
> > Hi Mansur,
> >
> > On 2020-06-13 16:03, Mansur Alisha Shaik wrote:
> > > After the SMMU translation is disabled in the
> > > arm-smmu shutdown callback during reboot, if
> > > any subsystem are still alive then IOVAs they
> > > are using will become PAs on bus, which may
> > > lead to crash.
> > >
> > > Below are the consumers of smmu from venus
> > > arm-smmu: consumer: aa00000.video-codec supplier=15000000.iommu
> > > arm-smmu: consumer: video-firmware.0 supplier=15000000.iommu
> > >
> > > So implemented shutdown callback, which detach iommu maps.
> > >
> > > Change-Id: I0f0f331056e0b84b92f1d86f66618d4b1caaa24a
> > > Signed-off-by: Mansur Alisha Shaik <mansur@xxxxxxxxxxxxxx>
> > > ---
> > >  drivers/media/platform/qcom/venus/core.c | 9 +++++++++
> > >  1 file changed, 9 insertions(+)
> > >
> > > diff --git a/drivers/media/platform/qcom/venus/core.c
> > > b/drivers/media/platform/qcom/venus/core.c
> > > index 30d4b9e..acf798c 100644
> > > --- a/drivers/media/platform/qcom/venus/core.c
> > > +++ b/drivers/media/platform/qcom/venus/core.c
> > > @@ -371,6 +371,14 @@ static int venus_remove(struct platform_device 
> > > *pdev)
> > >  	return ret;
> > >  }
> > >
> > > +static void venus_core_shutdown(struct platform_device *pdev)
> > > +{
> > > +	int ret;
> > > +
> > > +	ret = venus_remove(pdev);
> > > +	WARN_ON(ret < 0);
> >
> > I don't think you should warn here, its shutdown path and you can't
> > do anything with this WARN unlike remove callback where you have
> > to be sure to cleanup properly so that you are able to reload module.
> > But if you still want a hint about this failure, then just add a 
> > dev_err()
> > to indicate the failure instead of a big stack trace spamming kernel 
> > log.

posted V2 version by adding dev_warn during shutdown failure instead of 
WARN_ON.
V2 version : https://lore.kernel.org/patchwork/patch/1284693/

> > Thanks,
> > Sai

---
Thanks,
Mansur