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

[Hans de Goede <hdegoede@redhat.com>]

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@linux.intel.com>

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@vger.kernel.org
>> Cc: Daniel Drake <drake@endlessm.com>
>> Cc: Ian W MORRISON <ianwmorrison@gmail.com>
>> Reported-by: Ian W MORRISON <ianwmorrison@gmail.com>
>> Suggested-by: Ian W MORRISON <ianwmorrison@gmail.com>
>> Fixes: ca876c7483b6 ("gpiolib-acpi: make sure we trigger edge events at least once on boot")
>> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
>> ---
>> 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@linux.intel.com>
>>    */
>>   
>> +#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
>>
>