Re: [REGRESSION/PATCH] acpi: blacklist win8 OSI for ASUS Zenbok Prime UX31A

[Aaron Lu <aaron.lu@intel.com>]

On 10/21/2013 06:16 AM, Vincent Blut wrote:
> 
>> Since v3.7 the acpi backlight driver doesn't work at all on this machine
>> because presumably the ACPI code contains stub code when Windows 8 OSI is
>> reported.
>>
>> The commit ea45ea7 (in v3.11-rc2) tried to fix this problem by using the intel
>> backlight driver, however, on this machine it turns the backlight completely
>> off when it reaches level 0%, after which the user might have a lot trouble
>> trying to bring it back.
>>
>> This patch fixes both regressions by blacklisting the win8 OSI, so we are back
>> to v3.6 behavior, and it should remain that way until the intel backlight
>> driver is fixed.
>>
>> Since v3.7, users have been forced to fix the initial regression by modifying
>> the boot arguments [1].
>>
>> [1] https://wiki.archlinux.org/index.php/ASUS_Zenbook_Prime_UX31A
>>
>> Signed-off-by: Felipe Contreras <felipe.contreras@xxxxxxxxx>
>> ---
>>  drivers/acpi/blacklist.c | 14 ++++++++++++++
>>  1 file changed, 14 insertions(+)
>>
>> diff --git a/drivers/acpi/blacklist.c b/drivers/acpi/blacklist.c
>> index cb96296..a404127 100644
>> --- a/drivers/acpi/blacklist.c
>> +++ b/drivers/acpi/blacklist.c
>> @@ -192,6 +192,12 @@ static int __init dmi_disable_osi_win7(const struct dmi_system_id *d)
>>  	acpi_osi_setup("!Windows 2009");
>>  	return 0;
>>  }
>> +static int __init dmi_disable_osi_win8(const struct dmi_system_id *d)
>> +{
>> +	printk(KERN_NOTICE PREFIX "DMI detected: %s\n", d->ident);
>> +	acpi_osi_setup("!Windows 2012");
>> +	return 0;
>> +}
>>  
>>  static struct dmi_system_id acpi_osi_dmi_table[] __initdata = {
>>  	{
>> @@ -267,6 +273,14 @@ static struct dmi_system_id acpi_osi_dmi_table[] __initdata = {
>>  		     DMI_MATCH(DMI_PRODUCT_NAME, "Satellite P305D"),
>>  		},
>>  	},
>> +	{
>> +	.callback = dmi_disable_osi_win8,
>> +	.ident = "ASUS Zenbook Prime UX31A",
>> +	.matches = {
>> +		     DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
>> +		     DMI_MATCH(DMI_PRODUCT_NAME, "UX31A"),
>> +		},
>> +	},
>>  
>>  	/*
>>  	 * BIOS invocation of _OSI(Linux) is almost always a BIOS bug.
>> -- 
>> 1.8.3.4
> 
> Felipe, Rafaël,
> 
> I wonder if this quirk is still needed‽ I'm the owner of an Asus UX31A and of course,
> I used to set acpi_osi="!Windows 2012" on the kernel command line in order to change
> the backlight level. *However* since Linux 3.11, this kernel parameter is not needed
> anymore to influence it. The following commit seems to be the one that fixed (or at 
> least inhibited) the issue:
> 
> commit	efaa14c7e981bdf8d3c8d39d3ed12bdc60faabb8
> ACPI / video: no automatic brightness changes by win8-compatible firmware
> 
> Indeed, I reverted it on top of 3.11.6 and I can't change the backlight level anymore
> on this system!
> 
> Please see [1] for more information on what does that commit change in the way to control
> the backlight level.
> 
> So, is this inherent to my system? thought?

I don't think ASUS UX31A needs that quirk anymore.

Thanks,
Aaron

> 
> Cheers,
> Vincent
> 
> [1]http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=702188
> 
> 
> 
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