linux-kernel - Re: [UPDATE PATCH v2 1/3] ACPICA: Events: Introduce acpi_mask

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Date:	Sat, 16 Jul 2016 02:55:06 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Lv Zheng <lv.zheng@...el.com>
Cc:	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Len Brown <len.brown@...el.com>, Lv Zheng <zetalog@...il.com>,
	linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org
Subject: Re: [UPDATE PATCH v2 1/3] ACPICA: Events: Introduce acpi_mask_gpe() to implement GPE masking mechanism

On Monday, July 04, 2016 03:59:07 PM Rafael J. Wysocki wrote:
> On Thursday, June 23, 2016 03:05:47 PM Lv Zheng wrote:
> > (remove acpi_unmask_gpe() from the patch description)
> > 
> > There is a facility in Linux, developers can control the enabling/disabling
> > of a GPE via /sys/firmware/acpi/interrupts/gpexx. This is mainly for
> > debugging purposes.
> > 
> > But many users expect to use this facility to implement quirks to mask a
> > specific GPE when there is a gap in Linux causing this GPE to flood. This
> > is not working correctly because currently this facility invokes
> > enabling/disabling counting based GPE driver APIs:
> >  acpi_enable_gpe()/acpi_disable_gpe()
> > and the GPE drivers can still affect the count to mess up the GPE
> > masking purposes.
> > 
> > However, most of the IRQ chip designs allow masking/unmasking IRQs via a
> > masking bit which is different from the enabled bit to achieve the same
> > purpose. But the GPE hardware doesn't contain such a feature, this brings
> > the trouble.
> > 
> > In this patch, we introduce a software mechanism to implement the GPE
> > masking feature, and acpi_mask_gpe() are provided to the OSPMs to
> > mask/unmask GPEs in the above mentioned situation instead of
> > acpi_enable_gpe()/acpi_disable_gpe(). ACPICA BZ 1102. Lv Zheng.
> > 
> > Link: https://bugs.acpica.org/show_bug.cgi?id=1102
> > Signed-off-by: Lv Zheng <lv.zheng@...el.com>
> 
> I've queued up this one and the [2/3] and please see my comments on the [3/3].

I've decided that it's better if this goes in via upstream ACPICA, so it's not
in the queue any more.

For the time being, I'd like all changes in the ACPICA code to go in via the
upstream.

Thanks,
Rafael