linux-kernel - [PATCH] Skip deferred request irqs for devices known to fail

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Date:   Fri, 22 Mar 2019 22:05:15 +1100
From:   Ian W MORRISON <ianwmorrison@...il.com>
To:     benjamin.tissoires@...hat.com, hdegoede@...hat.com,
        mika.westerberg@...ux.intel.com, andriy.shevchenko@...ux.intel.com,
        linus.walleij@...aro.org, bgolaszewski@...libre.com
Cc:     linux-gpio@...r.kernel.org, linux-acpi@...r.kernel.org,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Ian W MORRISON <ianwmorrison@...il.com>
Subject: [PATCH] Skip deferred request irqs for devices known to fail

Patch ca876c7483b6 "gpiolib-acpi: make sure we trigger edge events at
least once on boot" causes the MINIX family of mini PCs to fail to boot
resulting in a "black screen". 

This patch excludes MINIX devices from executing this trigger in order
to successfully boot.

Cc: stable@...r.kernel.org
Signed-off-by: Ian W MORRISON <ianwmorrison@...il.com>
---
 drivers/gpio/gpiolib-acpi.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
index 259cf6ab969b..8d855dc9b020 100644
--- a/drivers/gpio/gpiolib-acpi.c
+++ b/drivers/gpio/gpiolib-acpi.c
@@ -16,9 +16,21 @@
 #include <linux/interrupt.h>
 #include <linux/mutex.h>
 #include <linux/pinctrl/pinctrl.h>
+#include <linux/dmi.h>
 
 #include "gpiolib.h"
 
+static const struct dmi_system_id skip_deferred_request_irqs_table[] = {
+	{
+		.ident = "MINIX Z83-4",
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "MINIX"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Z83-4"),
+		},
+	},
+	{}
+};
+
 /**
  * struct acpi_gpio_event - ACPI GPIO event handler data
  *
@@ -1219,18 +1231,24 @@ bool acpi_can_fallback_to_crs(struct acpi_device *adev, const char *con_id)
 }
 
 /* Run deferred acpi_gpiochip_request_irqs() */
+/* but exclude devices known to fail */
 static int acpi_gpio_handle_deferred_request_irqs(void)
 {
 	struct acpi_gpio_chip *acpi_gpio, *tmp;
+	const struct dmi_system_id *dmi_id;
 
-	mutex_lock(&acpi_gpio_deferred_req_irqs_lock);
-	list_for_each_entry_safe(acpi_gpio, tmp,
+	dmi_id = dmi_first_match(skip_deferred_request_irqs_table);
+
+	if (! dmi_id) {
+		mutex_lock(&acpi_gpio_deferred_req_irqs_lock);
+		list_for_each_entry_safe(acpi_gpio, tmp,
 				 &acpi_gpio_deferred_req_irqs_list,
 				 deferred_req_irqs_list_entry)
-		acpi_gpiochip_request_irqs(acpi_gpio);
+			acpi_gpiochip_request_irqs(acpi_gpio);
 
-	acpi_gpio_deferred_req_irqs_done = true;
-	mutex_unlock(&acpi_gpio_deferred_req_irqs_lock);
+		acpi_gpio_deferred_req_irqs_done = true;
+		mutex_unlock(&acpi_gpio_deferred_req_irqs_lock);
+	}
 
 	return 0;
 }
-- 
2.17.1