Re: [PATCH v2 6/8] PCI: acpiphp: workaround for Thunderbolt on Acer Aspire S5

[Rafael J. Wysocki]

On Thursday, July 04, 2013 11:58:44 AM Mika Westerberg wrote:
> On Wed, Jul 03, 2013 at 11:40:42PM +0200, Rafael J. Wysocki wrote:
> > On Wednesday, July 03, 2013 05:04:53 PM Mika Westerberg wrote:
> > > From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
> > > 
> > > Correct ACPI PCI hotplug imeplementation should have _RMV method in a
> > > PCI slot (device under pci bridge). In Acer Aspire S5 case we have it
> > > deeper in hierarchy:
> > > 
> > > Device (RP05)
> > > {
> > >    // ...
> > >    Device (HRUP)
> > >    {
> > >        // ...
> > >        Device (HRDN)
> > >        {
> > >            // ...
> > >            Device (EPUP)
> > >            {
> > >                // ...
> > >                Method (_RMV, 0, NotSerialized)  // _RMV: Removal Status
> > >                {
> > >                    Return (One)
> > >                }
> > >            }
> > >        }
> > >    }
> > > }
> > > 
> > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> > > Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> > > ---
> > >  drivers/pci/hotplug/acpi_pcihp.c | 13 +++++++++++++
> > >  1 file changed, 13 insertions(+)
> > > 
> > > diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> > > index 2a47e82..d92ebfb 100644
> > > --- a/drivers/pci/hotplug/acpi_pcihp.c
> > > +++ b/drivers/pci/hotplug/acpi_pcihp.c
> > > @@ -422,6 +422,19 @@ static int pcihp_is_ejectable(acpi_handle handle)
> > >  	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> > >  	if (ACPI_SUCCESS(status) && removable)
> > >  		return 1;
> > > +
> > > +	/*
> > > +	 * Workaround for Thunderbolt implementation on Acer Aspire S5.
> > > +	 *
> > > +	 * Correct ACPI PCI hotplug imeplementation has _RMV method in a PCI
> > > +	 * slot (device under pci bridge). In Acer Aspire S5 case we have it
> > > +	 * deeper in hierarchy.
> > > +	 */
> > > +	status = acpi_evaluate_integer(handle, "HRDN.EPUP._RMV", NULL,
> > > +			&removable);
> > 
> > Well, calling stuff like this directly from a general function is kind of ugly.
> > 
> > Can we use something like a quirk instead?  A DMI check or something?
> 
> Sure we can. How about something like the patch below?

Well, it goes into the right (to me) direction. :-)

Some comments below.

> From: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> Subject: [PATCH] PCI: acpiphp: workaround for Thunderbolt on Acer Aspire S5
> 
> The acpiphp driver finds out whether the device is removable by checking
> whether it has _RMV method directly behind it (and if it returns 1).
> However, at least on Acer Aspire S5 with Thunderbolt host router has this
> method placed behind a device called EPUP (endpoint upstream port?) and not
> in the usual place expected by the acpiphp driver. The ASL code below shows
> how this is done on that machine:
> 
> Device (RP05)
> {
> 	...
> 	Device (HRUP)
> 	{
> 		Name (_ADR, Zero)
> 		Name (_PRW, Package (0x02)
> 		{
> 			0x09,
> 			0x04
> 		})
> 		Device (HRDN)
> 		{
> 			Name (_ADR, 0x00040000)
> 			Name (_PRW, Package (0x02)
> 			{
> 				0x09,
> 				0x04
> 			})
> 			Device (EPUP)
> 			{
> 				Name (_ADR, Zero)
> 				Method (_RMV, 0, NotSerialized)
> 				{
> 					Return (One)
> 				}
> 			}
> 		}
> 	}
> 	...
> 
> Fix this by adding a DMI quirk for the Acer Aspire S5 machine that gives an
> alternative path to the _RMV method.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
> ---
>  drivers/pci/hotplug/acpi_pcihp.c | 57 ++++++++++++++++++++++++++++++++++++----
>  1 file changed, 52 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/pci/hotplug/acpi_pcihp.c b/drivers/pci/hotplug/acpi_pcihp.c
> index 2a47e82..99fccf3 100644
> --- a/drivers/pci/hotplug/acpi_pcihp.c
> +++ b/drivers/pci/hotplug/acpi_pcihp.c
> @@ -33,6 +33,7 @@
>  #include <linux/acpi.h>
>  #include <linux/pci-acpi.h>
>  #include <linux/slab.h>
> +#include <linux/dmi.h>
>  
>  #define MY_NAME	"acpi_pcihp"
>  
> @@ -408,21 +409,67 @@ got_one:
>  }
>  EXPORT_SYMBOL(acpi_get_hp_hw_control_from_firmware);
>  
> +/**
> + * pcihp_is_removable - is the given ACPI device removable
> + * @handle: ACPI handle of the device
> + *
> + * Try to find out whether the given ACPI device is removable by evaluating
> + * its _RMV and returning the result. If we can't find the _RMV directly
> + * under the device use system specific quirks to locate it.
> + */
> +static bool pcihp_is_removable(acpi_handle handle)
> +{

People are generally used to seeing DMI lists outside of functions.

> +	static const struct dmi_system_id rmv_paths[] = {
> +		{
> +			/*
> +			 * On Acer Aspire S5 the _RMV method for the
> +			 * Thunderbolt host router upstream port is not
> +			 * located directly under the device but it is
> +			 * instead placed a bit deeper in the hierarchy.
> +			 */
> +			.ident = "Acer Aspire S5",
> +			.matches = {
> +				DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
> +				DMI_MATCH(DMI_PRODUCT_NAME, "Aspire S5-391"),
> +			},
> +			.driver_data = "HRDN.EPUP._RMV",

Use .callback instead? ->

> +		},
> +		{ }
> +	};
> +	const struct dmi_system_id *id;
> +	unsigned long long removable;
> +	acpi_status status;
> +
> +	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> +	if (ACPI_SUCCESS(status))
> +		return !!removable;
> +
> +	/* Try system specific quirks */
> +	id = dmi_first_match(rmv_paths);
> +	if (id && id->driver_data) {

-> And here do

	if (id && id->callback)
		return id->callback(id);

> +		char path[64];
> +
> +		strlcpy(path, id->driver_data, sizeof(path));
> +		status = acpi_evaluate_integer(handle, path, NULL, &removable);
> +		if (ACPI_SUCCESS(status))
> +			return !!removable;
> +	}
> +
> +	return false;
> +}
> +
>  static int pcihp_is_ejectable(acpi_handle handle)
>  {
>  	acpi_status status;
>  	acpi_handle tmp;
> -	unsigned long long removable;
> +
>  	status = acpi_get_handle(handle, "_ADR", &tmp);
>  	if (ACPI_FAILURE(status))
>  		return 0;
>  	status = acpi_get_handle(handle, "_EJ0", &tmp);
>  	if (ACPI_SUCCESS(status))
>  		return 1;
> -	status = acpi_evaluate_integer(handle, "_RMV", NULL, &removable);
> -	if (ACPI_SUCCESS(status) && removable)
> -		return 1;

I'd keep the above unchanged and simply add a "platform check" function.

> -	return 0;
> +	return pcihp_is_removable(handle);
>  }
>  
>  /**

Thanks,
Rafael


-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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