linux-kernel - Re: [PATCH 3/3] ACPI / scan: Enable GPEs before scanning the namespace

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Date:   Tue, 15 Aug 2017 14:22:26 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     "Zheng, Lv" <lv.zheng@...el.com>
Cc:     Linux ACPI <linux-acpi@...r.kernel.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Linux PCI <linux-pci@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        "Moore, Robert" <robert.moore@...el.com>
Subject: Re: [PATCH 3/3] ACPI / scan: Enable GPEs before scanning the namespace

On Tuesday, August 15, 2017 4:12:24 AM CEST Zheng, Lv wrote:
> Hi, Rafael
> 
> > From: linux-acpi-owner@...r.kernel.org [mailto:linux-acpi-owner@...r.kernel.org] On Behalf Of Rafael J.
> > Wysocki
> > Subject: [PATCH 3/3] ACPI / scan: Enable GPEs before scanning the namespace
> > 
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > 
> > On some systems the platform firmware expects GPEs to be enabled
> > before the enumeration of devices and if that expectation is not
> > met, the systems in question may not boot in some situations.
> > 
> > For this reason, change the initialization ordering of the ACPI
> > subsystem to make it enable GPEs before scanning the namespace
> > for the first time in order to enumerate devices.
> > 
> > Reported-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
> > Suggested-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > ---
> >  drivers/acpi/scan.c |    8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> > 
> > Index: linux-pm/drivers/acpi/scan.c
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/scan.c
> > +++ linux-pm/drivers/acpi/scan.c
> > @@ -2139,6 +2139,10 @@ int __init acpi_scan_init(void)
> >  			acpi_get_spcr_uart_addr();
> >  	}
> > 
> > +	acpi_gpe_apply_masked_gpes();
> > +	acpi_update_all_gpes();
> > +	acpi_ec_ecdt_start();
> > +
> 
> Just for your information.
> A recent internal bug reveals that acpi_ec_ecdt_start() should only be
> invoked after the enumeration (acpi_ec_add()) for now.
> The function contains logics that need to be altered by acpi_ec_add().
> 
> So it seems we can only do less aggressive change by moving the GPE
> related 2 lines up.

OK, done.

Please check my linux-next branch and see if that's what it should be.

Thanks,
Rafael