Re: [PATCH v2] gpiolib: acpi: Add gpiolib_acpi_run_edge_events_on_boot option and blacklist

[Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>]

On Tue, Aug 27, 2019 at 10:28:35PM +0200, Hans de Goede wrote:
> Another day; another DSDT bug we need to workaround...
> 
> Since commit ca876c7483b6 ("gpiolib-acpi: make sure we trigger edge events
> at least once on boot") we call _AEI edge handlers at boot.
> 
> In some rare cases this causes problems. One example of this is the Minix
> Neo Z83-4 mini PC, this device has a clear DSDT bug where it has some copy
> and pasted code for dealing with Micro USB-B connector host/device role
> switching, while the mini PC does not even have a micro-USB connector.
> This code, which should not be there, messes with the DDC data pin from
> the HDMI connector (switching it to GPIO mode) breaking HDMI support.
> 
> To avoid problems like this, this commit adds a new
> gpiolib_acpi.run_edge_events_on_boot kernel commandline option, which
> allows disabling the running of _AEI edge event handlers at boot.
> 
> The default value is -1/auto which uses a DMI based blacklist, the initial
> version of this blacklist contains the Neo Z83-4 fixing the HDMI breakage.

Thank you!

Assuming it works for Ian,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>

> 
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Daniel Drake <drake@xxxxxxxxxxxx>
> Cc: Ian W MORRISON <ianwmorrison@xxxxxxxxx>
> Reported-by: Ian W MORRISON <ianwmorrison@xxxxxxxxx>
> Suggested-by: Ian W MORRISON <ianwmorrison@xxxxxxxxx>
> Fixes: ca876c7483b6 ("gpiolib-acpi: make sure we trigger edge events at least once on boot")
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> Changes in v2:
> - Use a module_param instead of __setup
> - Do DMI check only once from a postcore_initcall
> ---
>  drivers/gpio/gpiolib-acpi.c | 42 +++++++++++++++++++++++++++++++++----
>  1 file changed, 38 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
> index 39f2f9035c11..bda28eb82c3f 100644
> --- a/drivers/gpio/gpiolib-acpi.c
> +++ b/drivers/gpio/gpiolib-acpi.c
> @@ -7,6 +7,7 @@
>   *          Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
>   */
>  
> +#include <linux/dmi.h>
>  #include <linux/errno.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/gpio/driver.h>
> @@ -19,6 +20,11 @@
>  
>  #include "gpiolib.h"
>  
> +static int run_edge_events_on_boot = -1;
> +module_param(run_edge_events_on_boot, int, 0444);
> +MODULE_PARM_DESC(run_edge_events_on_boot,
> +		 "Run edge _AEI event-handlers at boot: 0=no, 1=yes, -1=auto");
> +
>  /**
>   * struct acpi_gpio_event - ACPI GPIO event handler data
>   *
> @@ -170,10 +176,13 @@ static void acpi_gpiochip_request_irq(struct acpi_gpio_chip *acpi_gpio,
>  	event->irq_requested = true;
>  
>  	/* Make sure we trigger the initial state of edge-triggered IRQs */
> -	value = gpiod_get_raw_value_cansleep(event->desc);
> -	if (((event->irqflags & IRQF_TRIGGER_RISING) && value == 1) ||
> -	    ((event->irqflags & IRQF_TRIGGER_FALLING) && value == 0))
> -		event->handler(event->irq, event);
> +	if (run_edge_events_on_boot &&
> +	    (event->irqflags & (IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING))) {
> +		value = gpiod_get_raw_value_cansleep(event->desc);
> +		if (((event->irqflags & IRQF_TRIGGER_RISING) && value == 1) ||
> +		    ((event->irqflags & IRQF_TRIGGER_FALLING) && value == 0))
> +			event->handler(event->irq, event);
> +	}
>  }
>  
>  static void acpi_gpiochip_request_irqs(struct acpi_gpio_chip *acpi_gpio)
> @@ -1283,3 +1292,28 @@ static int acpi_gpio_handle_deferred_request_irqs(void)
>  }
>  /* We must use _sync so that this runs after the first deferred_probe run */
>  late_initcall_sync(acpi_gpio_handle_deferred_request_irqs);
> +
> +static const struct dmi_system_id run_edge_events_on_boot_blacklist[] = {
> +	{
> +		.matches = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "MINIX"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "Z83-4"),
> +		}
> +	},
> +	{} /* Terminating entry */
> +};
> +
> +static int acpi_gpio_setup_params(void)
> +{
> +	if (run_edge_events_on_boot < 0) {
> +		if (dmi_check_system(run_edge_events_on_boot_blacklist))
> +			run_edge_events_on_boot = 0;
> +		else
> +			run_edge_events_on_boot = 1;
> +	}
> +
> +	return 0;
> +}
> +
> +/* Directly after dmi_setup() which runs as core_initcall() */
> +postcore_initcall(acpi_gpio_setup_params);
> -- 
> 2.23.0
> 

-- 
With Best Regards,
Andy Shevchenko