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

[Hans de Goede <hdegoede@xxxxxxxxxx>]

Hi,

On 28-08-19 13:37, Andy Shevchenko wrote:
> 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>

Note I have access to a Minix Neo Z83-4 myself now and I did test that
this fixes it and that passing gpiolib_acpi.run_edge_events_on_boot=0
breaks HDMI again (so the option works).

Regards,

Hans


> > 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