Re: [PATCH V2 2/4] ACPI/scan: Clean up acpi_check_dma

[Suravee Suthikulpanit]

Hi Rafael,

On 8/26/15 06:48, Rafael J. Wysocki wrote:

> [...]
> On Wednesday, August 26, 2015 12:33:27 AM Suravee Suthikulpanit wrote:
> > diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
> > index b9657af..55cf916 100644
> > --- a/drivers/acpi/glue.c
> > +++ b/drivers/acpi/glue.c
> > @@ -168,7 +168,7 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev)
> >   	struct list_head *physnode_list;
> >   	unsigned int node_id;
> >   	int retval = -EINVAL;
> > -	bool coherent;
> > +	int coherent;
>
> enum, anyone?  With clearly defined values?

Originally I had defined

enum acpi_dma_coherency {
	ACPI_DMA_NON_COHERENT,
	ACPI_DMA_COHERENT,
	APCI_DMA_NOT_SUPPORTED = -1,
};

Although, this would need to be defined in the include/linux/acpi.h, and 
will be used also for #ifndef CONFIG_ACPI code to return errors. I was 
not sure if this would be too much. If this is preferred, I'll add this 
back in.

> >   	if (has_acpi_companion(dev)) {
> >   		if (acpi_dev) {
> > @@ -225,7 +225,8 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev)
> >   	if (!has_acpi_companion(dev))
> >   		ACPI_COMPANION_SET(dev, acpi_dev);
> >
> > -	if (acpi_check_dma(acpi_dev, &coherent))
> > +	coherent = acpi_check_dma_coherency(acpi_dev);
> > +	if (coherent != -1)
>
> Like here I'm not sure why -1 is special?

It's just another value to communicate that DMA is not supported. :)

Thanks,
Suravee
> >   		arch_setup_dma_ops(dev, 0, 0, NULL, coherent);
> >
> >   	acpi_physnode_link_name(physical_node_name, node_id);
>
> Thanks,
> Rafael
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