Re: [patch 3/3] acpiphp: prevent duplicate slot numbers when no _SUN

[MUNEDA Takahiro <muneda.takahiro@jp.fujitsu.com>]

At Wed, 12 Apr 2006 15:18:47 -0700,
Kristen Accardi <kristen.c.accardi@intel.com> wrote:
> 
> Dock bridges generally do not implement _SUN, yet show up as ejectable slots.
> If you have more than one ejectable slot that does not implement SUN, with the
> current code you will get duplicate slot numbers.  So, if there is no _SUN,
> use the current count of the number of slots found instead.
> 
> Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
> 
> ---
>  drivers/pci/hotplug/acpiphp_glue.c |    9 +++++++--
>  1 files changed, 7 insertions(+), 2 deletions(-)
> 
> --- 2.6-git-kca2.orig/drivers/pci/hotplug/acpiphp_glue.c
> +++ 2.6-git-kca2/drivers/pci/hotplug/acpiphp_glue.c
> @@ -218,8 +218,13 @@ register_slot(acpi_handle handle, u32 lv
>  		newfunc->flags |= FUNC_HAS_DCK;
>  
>  	status = acpi_evaluate_integer(handle, "_SUN", NULL, &sun);
> -	if (ACPI_FAILURE(status))
> -		sun = -1;
> +	if (ACPI_FAILURE(status)) {
> +		/*
> +		 * use the count of the number of slots we've found
> +		 * for the number of the slot
> +		 */
> +		sun = bridge->nr_slots+1;
> +	}
>  
>  	/* search for objects that share the same slot */
>  	for (slot = bridge->slots; slot; slot = slot->next)
> 
> --

No, "sun = bridge->nr_slots+1" might have been defined for
another device. Please consider the following case.

  Device (PCI0) {                 /* Root bridge */
      Name (_HID, "PNP0A03")
      Device (P2PA) {             /* PCI-to-PCI bridge */
          Name (_ADR, ...)
          Device (S0F0) {         /* hotplug slot */
              Name (_ADR, ...)
              Name (_SUN, 0x01)
              Method (_EJ0, ...) { ... }
          }
          Device (S1F0) {         /* hotplug slot */
              Name (_ADR, ...)
              Name (_SUN, 0x02)
              Method (_EJ0, ...) { ... }
          }
          Device (GDCK) {         /* Docking Station */
              Method (_DCK, ...) { ... }
              Method (_EJ0, ...) { ... }
      }
      Device (P2PB) {             /* PCI-to-PCI bridge */
          Name (_ADR, ...)
          Device (S0F0) {         /* hotplug slot */
              Name (_ADR, ...)
              Name (_SUN, 0x03)
              Method (_EJ0, ...) { ... }
          }
          Device (S1F0) {         /* hotplug slot */
              Name (_ADR, ...)
              Name (_SUN, 0x04)
              Method (_EJ0, ...) { ... }
          }
      }
  }

In this case, there are two hotplug slots under the P2PA.
GDCK doesn't have SUN, so acpiphp sets SUN#3 for GDCK. But
SUN#3 is for the PCI0.P2PB.S0F0. sun is not unique!

But I have never seen the dsdt like above.

Thanks,
MUNE