linux-kernel - Re: [PATCH 3/3] Capture cable events created by Alienware GFX Amplifier.

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Date:	Thu, 28 May 2015 11:30:36 -0700
From:	Greg KH <greg@...ah.com>
To:	Mario Limonciello <mario_limonciello@...l.com>
Cc:	"matthew.garrett@...ula.com" <matthew.garrett@...ula.com>,
	LKML <linux-kernel@...r.kernel.org>,
	"platform-driver-x86@...r.kernel.org" 
	<platform-driver-x86@...r.kernel.org>
Subject: Re: [PATCH 3/3] Capture cable events created by Alienware GFX
 Amplifier.

On Wed, May 27, 2015 at 06:46:05PM -0500, Mario Limonciello wrote:
> 
> 
> On 05/27/2015 02:37 PM, Limonciello, Mario wrote:
> >These events are outputted via the keyboard controller.
> >Right now the only actionable event is to restart the system
> >if the cable is removed,  but the others are documented in
> >case they will be bubbled up to other parts of the kernel or
> >userspace later on.
> >
> >Signed-off-by: Mario Limonciello <mario_limonciello@...l.com>
> >---
> >  drivers/platform/x86/Kconfig         |  1 +
> >  drivers/platform/x86/alienware-wmi.c | 45 ++++++++++++++++++++++++++++++++++++
> >  2 files changed, 46 insertions(+)
> >
> >diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
> >index f9f205c..8a7bd7c 100644
> >--- a/drivers/platform/x86/Kconfig
> >+++ b/drivers/platform/x86/Kconfig
> >@@ -60,6 +60,7 @@ config ALIENWARE_WMI
> >  	depends on LEDS_CLASS
> >  	depends on NEW_LEDS
> >  	depends on ACPI_WMI
> >+	depends on SERIO_I8042
> >  	---help---
> >  	 This is a driver for controlling Alienware BIOS driven
> >  	 features.  It exposes an interface for controlling the AlienFX
> >diff --git a/drivers/platform/x86/alienware-wmi.c b/drivers/platform/x86/alienware-wmi.c
> >index 5bd8faf..ffccbd9 100644
> >--- a/drivers/platform/x86/alienware-wmi.c
> >+++ b/drivers/platform/x86/alienware-wmi.c
> >@@ -23,6 +23,8 @@
> >  #include <linux/dmi.h>
> >  #include <linux/acpi.h>
> >  #include <linux/leds.h>
> >+#include <linux/i8042.h>
> >+#include <linux/reboot.h>
> >  #define LEGACY_CONTROL_GUID		"A90597CE-A997-11DA-B012-B622A1EF5492"
> >  #define LEGACY_POWER_CONTROL_GUID	"A80593CE-A997-11DA-B012-B622A1EF5492"
> >@@ -650,6 +652,44 @@ error_create_amplifier:
> >  	return ret;
> >  }
> >+static bool alienware_i8042_filter(unsigned char data, unsigned char str,
> >+			struct serio *port)
> >+{
> >+	static bool extended;
> >+
> >+	if (str & I8042_STR_AUXDATA)
> >+		return false;
> >+
> >+	if (unlikely(data == 0xe0)) {
> >+		extended = true;
> >+		return false;
> >+	} else if (unlikely(extended)) {
> >+		switch (data) {
> >+		/*Connect */
> >+		case 0x3F:
> >+			pr_debug("Received connect event\n");
> >+			break;
> >+		/* Disconnect by hotkey */
> >+		case 0x40:
> >+			pr_debug("Received disconnect hotkey event\n");
> >+			break;
> >+		/*disconnect by cable undock button */
> >+		case 0x41:
> >+			pr_debug("Received disconnect button event\n");
> >+			break;
> >+		/* surprise disconnect */
> >+		case 0x42:
> >+			pr_crit("Graphics amplifier removed, initiating reboot.\n");
> >+			emergency_restart();
> 
> I had some discussion with someone in #systemd.  Just to clarify why the
> reboot is needed I wanted to mention it here.
> X does continue to run and the kernel doesn't panic, but the GPU drivers
> gets stuck in a hung state.

Then fix the GPU drivers.

> Restarting X or plugging the cable back in doesn't actually fix it.

Fix the GPU drivers.

> Since you just pulled your U/I from under yourself you don't really have a
> way to message what happened, or to fix this other than restarting the
> system.

Fix the GPU drivers.

> I also later discovered that this should probably be:
> 
>     orderly_reboot();

Nope, fix the GPU drivers.

> I'll resubmit with that change after any other discussion around iterating
> with this.

With a fix for the GPU drivers?  Great, that's the only acceptable
solution.

thanks,

greg k-h
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