Re: [PATCH] acpi: apei: check for pending errors when probing HED type GHES entries

[Baicar, Tyler]

On 3/28/2017 4:00 PM, Al Stone wrote:
> On 03/28/2017 02:14 PM, Tyler Baicar wrote:
> > If a HED type error occurs prior to GHES probing, the kernel will
> > never report the error. The HED driver will see that no notifiers
> > are registers, and clear the interrupt.
> ..."registers" or "registered"?
Oops :) I'll fix that to say registered.

Thanks,
Tyler
> > This becomes a more serious problem with firmware that supports
> > GHESv2 acknowledgements from the kernel. The firmware will populate
> > the error and wait for the kernel ack. But since the kernel will
> > never process the error we get into a state that the firmware will
> > not send any more errors and the kernel will never see or ack the
> > original error.
> >
> > Check for pending errors when probing HED type GHES entries to
> > avoid the above situation.
> >
> > This patch is based on Shiju's patch that adds support for GSIV
> > and GPIO notification types:
> > https://patchwork.kernel.org/patch/9628817/
> >
> > Signed-off-by: Tyler Baicar <tbaicar@xxxxxxxxxxxxxx>
> > ---
> >   drivers/acpi/apei/ghes.c | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> > index fd39929..cf5e938 100644
> > --- a/drivers/acpi/apei/ghes.c
> > +++ b/drivers/acpi/apei/ghes.c
> > @@ -1035,6 +1035,7 @@ static int ghes_probe(struct platform_device *ghes_dev)
> >   			register_acpi_hed_notifier(&ghes_notifier_hed);
> >   		list_add_rcu(&ghes->list, &ghes_hed);
> >   		mutex_unlock(&ghes_list_mutex);
> > +		ghes_proc(ghes);
> >   		break;
> >   	case ACPI_HEST_NOTIFY_NMI:
> >   		ghes_nmi_add(ghes);

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