linux-kernel - Re: [PATCH 1/4] ACPI: Support

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Date:	Tue, 17 Jun 2014 14:11:36 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Matthew Garrett <matthew.garrett@...ula.com>
Cc:	lenb@...nel.org, robert.moore@...el.com, lv.zheng@...el.com,
	linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org, bhelgaas@...gle.com
Subject: Re: [PATCH 1/4] ACPI: Support _OSI("Darwin") correctly

On Sunday, June 01, 2014 12:33:53 PM Matthew Garrett wrote:
> Apple hardware queries _OSI("Darwin") in order to determine whether the
> system is running OS X, and changes firmware behaviour based on the answer.
> The most obvious difference in behaviour is that Thunderbolt hardware is
> forcibly powered down unless the system is running OS X. The obvious solution
> would be to simply add Darwin to the list of supported _OSI strings, but this
> causes problems.
> 
> Recent Apple hardware includes two separate methods for checking _OSI
> strings. The first will check whether Darwin is supported, and if so will
> exit. The second will check whether Darwin is supported, but will then
> continue to check for further operating systems. If a further operating
> system is found then later firmware code will assume that the OS is not OS X.
> This results in the unfortunate situation where the Thunderbolt controller is
> available at boot time but remains powered down after suspend.
> 
> The easiest way to handle this is to special-case it in the Linux-specific
> OSI handling code. If we see Darwin, we should answer true and then disable
> all other _OSI vendor strings.
> 
> Signed-off-by: Matthew Garrett <matthew.garrett@...ula.com>

Does applying this patch without the rest of the series makes things worse
or better on the machines in question (or perhaps it doesn't matter at all
alone)?

Rafael


> ---
>  drivers/acpi/acpica/utosi.c |  1 +
>  drivers/acpi/osl.c          | 10 ++++++++++
>  include/acpi/actypes.h      | 25 +++++++++++++------------
>  3 files changed, 24 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/acpi/acpica/utosi.c b/drivers/acpi/acpica/utosi.c
> index 685766f..63b0a3b 100644
> --- a/drivers/acpi/acpica/utosi.c
> +++ b/drivers/acpi/acpica/utosi.c
> @@ -87,6 +87,7 @@ ACPI_MODULE_NAME("utosi")
>  static struct acpi_interface_info acpi_default_supported_interfaces[] = {
>  	/* Operating System Vendor Strings */
>  
> +	{"Darwin", NULL, 0, ACPI_OSI_DARWIN},	/* OS X */
>  	{"Windows 2000", NULL, 0, ACPI_OSI_WIN_2000},	/* Windows 2000 */
>  	{"Windows 2001", NULL, 0, ACPI_OSI_WIN_XP},	/* Windows XP */
>  	{"Windows 2001 SP1", NULL, 0, ACPI_OSI_WIN_XP_SP1},	/* Windows XP SP1 */
> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> index 6776c59..312ab5c 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -152,6 +152,16 @@ static u32 acpi_osi_handler(acpi_string interface, u32 supported)
>  			osi_linux.dmi ? " via DMI" : "");
>  	}
>  
> +	if (!strcmp("Darwin", interface)) {
> +		/*
> +		 * Apple firmware will behave poorly if it receives positive
> +		 * answers to "Darwin" and any other OS. Respond positively
> +		 * to Darwin and then disable all other vendor strings.
> +		 */
> +		acpi_update_interfaces(ACPI_DISABLE_ALL_VENDOR_STRINGS);
> +		supported = ACPI_UINT32_MAX;
> +	}
> +
>  	return supported;
>  }
>  
> diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h
> index e763565..1c2ef56 100644
> --- a/include/acpi/actypes.h
> +++ b/include/acpi/actypes.h
> @@ -1210,17 +1210,18 @@ struct acpi_memory_list {
>  #define ACPI_ENABLE_ALL_FEATURE_STRINGS     (ACPI_ENABLE_INTERFACES | ACPI_FEATURE_STRINGS)
>  #define ACPI_ENABLE_ALL_STRINGS             (ACPI_ENABLE_INTERFACES | ACPI_VENDOR_STRINGS | ACPI_FEATURE_STRINGS)
>  
> -#define ACPI_OSI_WIN_2000               0x01
> -#define ACPI_OSI_WIN_XP                 0x02
> -#define ACPI_OSI_WIN_XP_SP1             0x03
> -#define ACPI_OSI_WINSRV_2003            0x04
> -#define ACPI_OSI_WIN_XP_SP2             0x05
> -#define ACPI_OSI_WINSRV_2003_SP1        0x06
> -#define ACPI_OSI_WIN_VISTA              0x07
> -#define ACPI_OSI_WINSRV_2008            0x08
> -#define ACPI_OSI_WIN_VISTA_SP1          0x09
> -#define ACPI_OSI_WIN_VISTA_SP2          0x0A
> -#define ACPI_OSI_WIN_7                  0x0B
> -#define ACPI_OSI_WIN_8                  0x0C
> +#define ACPI_OSI_DARWIN                 0x01
> +#define ACPI_OSI_WIN_2000               0x02
> +#define ACPI_OSI_WIN_XP                 0x03
> +#define ACPI_OSI_WIN_XP_SP1             0x04
> +#define ACPI_OSI_WINSRV_2003            0x05
> +#define ACPI_OSI_WIN_XP_SP2             0x06
> +#define ACPI_OSI_WINSRV_2003_SP1        0x07
> +#define ACPI_OSI_WIN_VISTA              0x08
> +#define ACPI_OSI_WINSRV_2008            0x09
> +#define ACPI_OSI_WIN_VISTA_SP1          0x0A
> +#define ACPI_OSI_WIN_VISTA_SP2          0x0B
> +#define ACPI_OSI_WIN_7                  0x0C
> +#define ACPI_OSI_WIN_8                  0x0D
>  
>  #endif				/* __ACTYPES_H__ */
> 

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