linux-kernel - RE: [PATCH 2/2] platform/x86: dell-*: Add interface for switchable graphics status query

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Date:   Thu, 8 Mar 2018 08:35:51 +0000
From:   <Mario.Limonciello@...l.com>
To:     <kai.heng.feng@...onical.com>
CC:     <mjg59@...f.ucam.org>, <pali.rohar@...il.com>,
        <dvhart@...radead.org>, <andy@...radead.org>, <tiwai@...e.com>,
        <platform-driver-x86@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <alsa-devel@...a-project.org>
Subject: RE: [PATCH 2/2] platform/x86: dell-*: Add interface for switchable
 graphics status query

> -----Original Message-----
> From: Kai Heng Feng [mailto:kai.heng.feng@...onical.com]
> Sent: Thursday, March 8, 2018 4:20 PM
> To: Limonciello, Mario <Mario_Limonciello@...l.com>
> Cc: mjg59@...f.ucam.org; pali.rohar@...il.com; dvhart@...radead.org;
> andy@...radead.org; tiwai@...e.com; platform-driver-x86@...r.kernel.org; linux-
> kernel@...r.kernel.org; alsa-devel@...a-project.org
> Subject: Re: [PATCH 2/2] platform/x86: dell-*: Add interface for switchable graphics
> status query
> 
> 
> 
> > On Mar 8, 2018, at 3:34 PM, Mario.Limonciello@...l.com wrote:
> >
> >> -----Original Message-----
> >> From: Kai-Heng Feng [mailto:kai.heng.feng@...onical.com]
> >> Sent: Thursday, March 8, 2018 3:12 PM
> >> To: mjg59@...f.ucam.org; pali.rohar@...il.com; dvhart@...radead.org;
> >> andy@...radead.org; Limonciello, Mario <Mario_Limonciello@...l.com>;
> >> tiwai@...e.com
> >> Cc: platform-driver-x86@...r.kernel.org; linux-kernel@...r.kernel.org;
> >> alsa-
> >> devel@...a-project.org; Kai-Heng Feng <kai.heng.feng@...onical.com>
> >> Subject: [PATCH 2/2] platform/x86: dell-*: Add interface for switchable
> >> graphics
> >> status query
> >>
> >> On some Dell platforms, there's a BIOS option "Enable Switchable
> >> Graphics". This information is useful if we want to do different things
> >> based on this value, e.g. disable unused audio controller that comes
> >> with the discrete graphics.
> >
> > I was expecting the follow on patch that uses this interface too as part
> > of the
> > series. This patch itself however looks like.
> 
> I thought it should be easier to separate patch series for different
> subsystems.
> But of course I can make them the as one series.
> 
> I'll resend a v2 for this.
> 

At least in other subsystem in the kernel I've heard comments from
maintainer that it doesn't make sense to add code that no one uses.
I don't know if that's how Darren and Andy feel to. 

At worst case scenario patches 1 and 2 could be added while patch
3 iterates too.

> Kai-Heng
> 
> >
> > Reviewed-by: Mario Limonciello <mario.limonciello@...l.com>
> >> Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
> >> ---
> >>  drivers/platform/x86/dell-laptop.c | 23 +++++++++++++++++++++++
> >>  drivers/platform/x86/dell-smbios.c |  2 ++
> >>  drivers/platform/x86/dell-smbios.h |  2 ++
> >>  3 files changed, 27 insertions(+)
> >>
> >> diff --git a/drivers/platform/x86/dell-laptop.c
> >> b/drivers/platform/x86/dell-laptop.c
> >> index 8ba820e6c3d0..3f6fc07b8cf2 100644
> >> --- a/drivers/platform/x86/dell-laptop.c
> >> +++ b/drivers/platform/x86/dell-laptop.c
> >> @@ -2116,6 +2116,29 @@ int dell_micmute_led_set(int state)
> >>  }
> >>  EXPORT_SYMBOL_GPL(dell_micmute_led_set);
> >>
> >> +int dell_switchable_gfx_enabled(bool *enabled)
> >> +{
> >> +	struct calling_interface_buffer buffer;
> >> +	struct calling_interface_token *token;
> >> +	int ret;
> >> +
> >> +	*enabled = false;
> >> +
> >> +	token = dell_smbios_find_token(SWITCHABLE_GRAPHICS_ENABLE);
> >> +	if (!token)
> >> +		return -ENODEV;
> >> +
> >> +	dell_fill_request(&buffer, token->location, 0, 0, 0);
> >> +	ret = dell_send_request(&buffer, CLASS_TOKEN_READ,
> >> SELECT_TOKEN_STD);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	*enabled = !!buffer.output[1];
> >> +
> >> +	return 0;
> >> +}
> >> +EXPORT_SYMBOL_GPL(dell_switchable_gfx_enabled);
> >> +
> >>  static int __init dell_init(void)
> >>  {
> >>  	struct calling_interface_token *token;
> >> diff --git a/drivers/platform/x86/dell-smbios.c
> >> b/drivers/platform/x86/dell-smbios.c
> >> index 8541cde4cb7d..ca38b9d9dcf4 100644
> >> --- a/drivers/platform/x86/dell-smbios.c
> >> +++ b/drivers/platform/x86/dell-smbios.c
> >> @@ -86,6 +86,8 @@ struct token_range {
> >>  static struct token_range token_whitelist[] = {
> >>  	/* used by userspace: fwupdate */
> >>  	{CAP_SYS_ADMIN,	CAPSULE_EN_TOKEN,	CAPSULE_DIS_TOKEN},
> >> +	/* can indicate to userspace Switchable Graphics enable status */
> >> +	{CAP_SYS_ADMIN,	SWITCHABLE_GRAPHICS_ENABLE,
> >> 	SWITCHABLE_GRAPHICS_DISABLE},
> >>  	/* can indicate to userspace that WMI is needed */
> >>  	{0x0000,	WSMT_EN_TOKEN,		WSMT_DIS_TOKEN}
> >>  };
> >> diff --git a/drivers/platform/x86/dell-smbios.h
> >> b/drivers/platform/x86/dell-smbios.h
> >> index 138d478d9adc..b012d4abd239 100644
> >> --- a/drivers/platform/x86/dell-smbios.h
> >> +++ b/drivers/platform/x86/dell-smbios.h
> >> @@ -37,6 +37,8 @@
> >>  #define KBD_LED_AUTO_100_TOKEN	0x02F6
> >>  #define GLOBAL_MIC_MUTE_ENABLE	0x0364
> >>  #define GLOBAL_MIC_MUTE_DISABLE	0x0365
> >> +#define SWITCHABLE_GRAPHICS_ENABLE	0x037A
> >> +#define SWITCHABLE_GRAPHICS_DISABLE	0x037B
> >>
> >>  struct notifier_block;
> >>
> >> --
> >> 2.15.1