linux-kernel - [PATCH v2 1/1] gpio: Request interrupts after IRQ is initialized

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Date:   Fri, 22 Apr 2022 08:14:52 -0500
From:   Mario Limonciello <mario.limonciello@....com>
To:     <torvalds@...ux-foundation.org>
CC:     Natikar Basavaraj <Basavaraj.Natikar@....com>,
        Gong Richard <Richard.Gong@....com>,
        <regressions@...ts.linux.dev>,
        Thorsten Leemhuis <regressions@...mhuis.info>,
        Greg KH <gregkh@...uxfoundation.org>, <stable@...r.kernel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        "Bartosz Golaszewski" <brgl@...ev.pl>,
        Shreeya Patel <shreeya.patel@...labora.com>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        "Mario Limonciello" <mario.limonciello@....com>,
        Samuel Čavoj <samuel@...oj.net>,
        <lukeluk498@...il.com>
Subject: [PATCH v2 1/1] gpio: Request interrupts after IRQ is initialized

commit 5467801f1fcb ("gpio: Restrict usage of GPIO chip irq members before
initialization") attempted to fix a race condition that lead to a NULL
pointer, but in the process caused a regression for _AEI/_EVT declared
GPIOs. This manifests in messages showing deferred probing while trying
to allocate IRQs like so:

[    0.688318] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x0000 to IRQ, err -517
[    0.688337] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x002C to IRQ, err -517
[    0.688348] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x003D to IRQ, err -517
[    0.688359] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x003E to IRQ, err -517
[    0.688369] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x003A to IRQ, err -517
[    0.688379] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x003B to IRQ, err -517
[    0.688389] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x0002 to IRQ, err -517
[    0.688399] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x0011 to IRQ, err -517
[    0.688410] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x0012 to IRQ, err -517
[    0.688420] amd_gpio AMDI0030:00: Failed to translate GPIO pin 0x0007 to IRQ, err -517

The code for walking _AEI doesn't handle deferred probing and so this leads
to non-functional GPIO interrupts.

Fix this issue by moving the call to `acpi_gpiochip_request_interrupts` to
occur after gc->irc.initialized is set.

Cc: Shreeya Patel <shreeya.patel@...labora.com>
Cc: stable@...r.kernel.org
Fixes: 5467801f1fcb ("gpio: Restrict usage of GPIO chip irq members before initialization")
Reported-by: Mario Limonciello <mario.limonciello@....com>
Link: https://lore.kernel.org/linux-gpio/BL1PR12MB51577A77F000A008AA694675E2EF9@BL1PR12MB5157.namprd12.prod.outlook.com/T/#u
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
Reviewed-by: Shreeya Patel <shreeya.patel@...labora.com>
Tested-By: Samuel Čavoj <samuel@...oj.net>
Tested-By: lukeluk498@...il.com Link:
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1979
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215850
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/1976
Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
Acked-by: Linus Walleij <linus.walleij@...aro.org>
---
v1->v2:
 * Pick up acked-by/reviewed-by/link/tested-by

 drivers/gpio/gpiolib.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 085348e08986..b7694171655c 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1601,8 +1601,6 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
 
 	gpiochip_set_irq_hooks(gc);
 
-	acpi_gpiochip_request_interrupts(gc);
-
 	/*
 	 * Using barrier() here to prevent compiler from reordering
 	 * gc->irq.initialized before initialization of above
@@ -1612,6 +1610,8 @@ static int gpiochip_add_irqchip(struct gpio_chip *gc,
 
 	gc->irq.initialized = true;
 
+	acpi_gpiochip_request_interrupts(gc);
+
 	return 0;
 }
 
-- 
2.34.1