linux-kernel - Re: [PATCH 2/2] ACPI: Ignore Consumer/Producer for QWord/DWord/Word Address Space

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Message-ID: <20161130162436.GA9093@red-moon>
Date:   Wed, 30 Nov 2016 16:24:36 +0000
From:   Lorenzo Pieralisi <lorenzo.pieralisi@....com>
To:     Bjorn Helgaas <helgaas@...nel.org>
Cc:     Bjorn Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org,
        linaro-acpi@...ts.linaro.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-acpi@...r.kernel.org
Subject: Re: [PATCH 2/2] ACPI: Ignore Consumer/Producer for QWord/DWord/Word
 Address Space

On Wed, Nov 30, 2016 at 09:56:17AM -0600, Bjorn Helgaas wrote:
> On Wed, Nov 30, 2016 at 12:04:25PM +0000, Lorenzo Pieralisi wrote:
> > On Tue, Nov 29, 2016 at 12:43:34PM -0600, Bjorn Helgaas wrote:
> > > Per ACPI spec r6.0, sec 6.4.3.5.1, 2, 3, Bit [0] of General Flags (the
> > > Consumer/Producer bit) should be ignored for QWord/DWord/Word Address Space
> > > descriptors.  The Consumer/Producer bit is defined only for the Extended
> > > Address Space descriptor.
> > > 
> > > Ignore Consumer/Producer except for Extended Address Space descriptors.
> > > 
> > > Note that for QWord/DWord/Word descriptors, we previously applied the
> > > translation offset (_TRA) only when the Consumer/Producer bit was set.
> > 
> > "..Consumer/Producer bit was clear" ? If that bit was set:
> > 
> > struct acpi_resource_address->producer_consumer == ACPI_CONSUMER
> > 
> > and we are not applying the _TRA offset in that case, right ?
> 
> Right, of course.  How about this instead?
> 
>     Note that for QWord/DWord/Word descriptors, we previously applied the
>     translation offset (_TRA) only for Producers, i.e., when the Consumer/
>     Producer bit was clear.  This patch changes that: for those descriptors,
>     we ignore Consumer/Producer and always apply the translation offset.

Yes that's a perfect description, thanks a lot !

Lorenzo

> > > This patch changes that: for those descriptors, we ignore Consumer/Producer
> > > and always apply the translation offset.
> > > 
> > > Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
> > > ---
> > >  drivers/acpi/resource.c |   16 +++++++++++-----
> > >  1 file changed, 11 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
> > > index 2732d39e..b45cd8f 100644
> > > --- a/drivers/acpi/resource.c
> > > +++ b/drivers/acpi/resource.c
> > > @@ -261,11 +261,16 @@ bool acpi_dev_resource_address_space(struct acpi_resource *ares,
> > >  	 * primary side. Non-bridge devices must list 0 for all Address
> > >  	 * Translation offset bits.
> > >  	 */
> > > -	if (addr->producer_consumer == ACPI_PRODUCER)
> > > +	if (ares->type == ACPI_RESOURCE_TYPE_EXTENDED_ADDRESS64) {
> > > +		if (addr->producer_consumer == ACPI_PRODUCER)
> > > +			offset = attr->translation_offset;
> > > +		else if (attr->translation_offset)
> > > +			pr_debug("ACPI: translation_offset(%lld) is invalid for non-bridge device.\n",
> > > +				 attr->translation_offset);
> > > +	} else {
> > >  		offset = attr->translation_offset;
> > > -	else if (attr->translation_offset)
> > > -		pr_debug("ACPI: translation_offset(%lld) is invalid for non-bridge device.\n",
> > > -			 attr->translation_offset);
> > > +	}
> > > +
> > >  	start = attr->minimum + offset;
> > >  	end = attr->maximum + offset;
> > >  
> > > @@ -294,7 +299,8 @@ bool acpi_dev_resource_address_space(struct acpi_resource *ares,
> > >  		return false;
> > >  	}
> > >  
> > > -	if (addr->producer_consumer == ACPI_PRODUCER)
> > > +	if (ares->type == ACPI_RESOURCE_TYPE_EXTENDED_ADDRESS64 &&
> > > +	    addr->producer_consumer == ACPI_PRODUCER)
> > >  		res->flags |= IORESOURCE_WINDOW;
> > >  
> > >  	if (addr->info.mem.caching == ACPI_PREFETCHABLE_MEMORY)
> > > 
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe linux-pci" in
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> > 
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@...ts.infradead.org
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