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From:   Jian-Hong Pan <jian-hong@endlessm.com>
To:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>
Cc:     x86@kernel.org, linux-kernel@vger.kernel.org, linux@endlessm.com,
        Jian-Hong Pan <jian-hong@endlessm.com>,
        Daniel Drake <drake@endlessm.com>
Subject: [PATCH] x86/reboot: Use efi reboot for Acer TravelMate X514-51T
Date:   Mon,  1 Apr 2019 15:35:14 +0800
Message-Id: <20190401073514.2785-1-jian-hong@endlessm.com>
MIME-Version: 1.0
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Upon reboot, the Acer TravelMate X514-51T laptop appears to complete the
shutdown process, but then it hangs in BIOS POST with a black screen.

The problem is intermittent - at some points it has appeared related to
Secure Boot settings or different kernel builds, but ultimately we have
not been able to identify the exact conditions that trigger the issue to
come and go.

However, after extensive testing, we observe that using the EFI reboot
method reliably avoids the issue in all cases.

Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=203119
Signed-off-by: Jian-Hong Pan <jian-hong@endlessm.com>
Signed-off-by: Daniel Drake <drake@endlessm.com>
---
 arch/x86/kernel/reboot.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
index 725624b6c0c0..145bdfb56a9a 100644
--- a/arch/x86/kernel/reboot.c
+++ b/arch/x86/kernel/reboot.c
@@ -81,6 +81,19 @@ static int __init set_bios_reboot(const struct dmi_system_id *d)
 	return 0;
 }
 
+/*
+ * Some machines require the "reboot=e" commandline options
+ */
+static int __init set_efi_reboot(const struct dmi_system_id *d)
+{
+	if (reboot_type != BOOT_EFI) {
+		reboot_type = BOOT_EFI;
+		pr_info("%s series board detected. Selecting %s-method for reboot.\n",
+			d->ident, "EFI");
+	}
+	return 0;
+}
+
 void __noreturn machine_real_restart(unsigned int type)
 {
 	local_irq_disable();
@@ -166,6 +179,14 @@ static const struct dmi_system_id reboot_dmi_table[] __initconst = {
 			DMI_MATCH(DMI_PRODUCT_NAME, "AOA110"),
 		},
 	},
+	{	/* Handle reboot issue on Acer TravelMate X514-51T */
+		.callback = set_efi_reboot,
+		.ident = "Acer TravelMate X514-51T",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "TravelMate X514-51T"),
+		},
+	},
 
 	/* Apple */
 	{	/* Handle problems with rebooting on Apple MacBook5 */
-- 
2.20.1