linux-kernel - Re: [PATCH] PCI/ACPI: Report ASPM support to BIOS if not disabled from command line

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Date:	Fri, 18 Mar 2011 10:10:20 +0900
From:	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
To:	Jesse Barnes <jbarnes@...tuousgeek.org>
CC:	"Rafael J. Wysocki" <rjw@...k.pl>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux PM mailing list <linux-pm@...ts.linux-foundation.org>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	linux-pci@...r.kernel.org
Subject: Re: [PATCH] PCI/ACPI: Report ASPM support to BIOS if not disabled
 from command line

Jesse,

This patch fixes the problem that PCIe hotplug no longer work in 2.6.38
on my platform (ASPM is disabled　through ACPI FADT in my platform).
I think this need to be applied soon.

Reviewed-by: Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>
Tested-by: Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>

Regards,
Kenji Kaneshige


(2011/03/05 21:21), Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki<rjw@...k.pl>
>
> We need to distinguish the situation in which ASPM support is
> disabled from the command line or through .config from the situation
> in which it is disabled, because the hardware or BIOS can't handle
> it.  In the former case we should not report ASPM support to the BIOS
> through ACPI _OSC, but in the latter case we should do that.
>
> Introduce pcie_aspm_support_enabled() that can be used by
> acpi_pci_root_add() to determine whether or not it should report ASPM
> support to the BIOS through _OSC.
>
> References: https://bugzilla.kernel.org/show_bug.cgi?id=29722
> References: https://bugzilla.kernel.org/show_bug.cgi?id=20232
> Reported-and-tested-by: Ortwin Glück<odi@....ch>
> Signed-off-by: Rafael J. Wysocki<rjw@...k.pl>
> ---
>   drivers/acpi/pci_root.c |    2 +-
>   drivers/pci/pcie/aspm.c |    7 +++++++
>   include/linux/pci.h     |    7 +++----
>   3 files changed, 11 insertions(+), 5 deletions(-)
>
> Index: linux-2.6/drivers/pci/pcie/aspm.c
> ===================================================================
> --- linux-2.6.orig/drivers/pci/pcie/aspm.c
> +++ linux-2.6/drivers/pci/pcie/aspm.c
> @@ -69,6 +69,7 @@ struct pcie_link_state {
>   };
>
>   static int aspm_disabled, aspm_force, aspm_clear_state;
> +static bool aspm_support_enabled = true;
>   static DEFINE_MUTEX(aspm_lock);
>   static LIST_HEAD(link_list);
>
> @@ -896,6 +897,7 @@ static int __init pcie_aspm_disable(char
>   {
>   	if (!strcmp(str, "off")) {
>   		aspm_disabled = 1;
> +		aspm_support_enabled = false;
>   		printk(KERN_INFO "PCIe ASPM is disabled\n");
>   	} else if (!strcmp(str, "force")) {
>   		aspm_force = 1;
> @@ -930,3 +932,8 @@ int pcie_aspm_enabled(void)
>   }
>   EXPORT_SYMBOL(pcie_aspm_enabled);
>
> +bool pcie_aspm_support_enabled(void)
> +{
> +	return aspm_support_enabled;
> +}
> +EXPORT_SYMBOL(pcie_aspm_support_enabled);
> Index: linux-2.6/drivers/acpi/pci_root.c
> ===================================================================
> --- linux-2.6.orig/drivers/acpi/pci_root.c
> +++ linux-2.6/drivers/acpi/pci_root.c
> @@ -564,7 +564,7 @@ static int __devinit acpi_pci_root_add(s
>   	/* Indicate support for various _OSC capabilities. */
>   	if (pci_ext_cfg_avail(root->bus->self))
>   		flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
> -	if (pcie_aspm_enabled())
> +	if (pcie_aspm_support_enabled())
>   		flags |= OSC_ACTIVE_STATE_PWR_SUPPORT |
>   			OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
>   	if (pci_msi_enabled())
> Index: linux-2.6/include/linux/pci.h
> ===================================================================
> --- linux-2.6.orig/include/linux/pci.h
> +++ linux-2.6/include/linux/pci.h
> @@ -1002,12 +1002,11 @@ extern bool pcie_ports_auto;
>   #endif
>
>   #ifndef CONFIG_PCIEASPM
> -static inline int pcie_aspm_enabled(void)
> -{
> -	return 0;
> -}
> +static inline int pcie_aspm_enabled(void) { return 0; }
> +static inline bool pcie_aspm_support_enabled(void) { return false; }
>   #else
>   extern int pcie_aspm_enabled(void);
> +extern bool pcie_aspm_support_enabled(void);
>   #endif
>
>   #ifdef CONFIG_PCIEAER
> --
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>
>


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