Re: [PATCH] Revert "ACPI / video: Add HP EliteBook Revolve 810 to the blacklist"

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Fri, Feb 14, 2014 at 02:37:00PM +0100, Takashi Iwai wrote:
> At Fri, 14 Feb 2014 14:34:07 +0200,
> Mika Westerberg wrote:
> > 
> > This reverts commit e18ac62fa4b3f16234bab0d5a6627c57dbae9e7e.
> > 
> > The referenced commit added HP EliteBook Revolve 810 to the ACPI video
> > detected blacklist so that only the native Intel backlight interface was
> > exported.
> > 
> > However, this turned to be wrong solution after all. The ACPI video
> > interface works and as long as we only use that there are no problems. So
> > we can revert this commit and stick to use the backlight interface provided
> > by the ACPI video driver.
> > 
> > (Using Intel native interface will not work after resume since the ACPI
> > video driver will restore it's state which takes control over the native
> > one. That's a separate thing and should be addressed in the ACPI video
> > driver, I suppose.)
> > 
> > References: https://bugzilla.kernel.org/show_bug.cgi?id=70231
> > Cc: Aaron Lu <aaron.lu@intel.com>
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > ---
> > Rafael, 
> > 
> > This turned out to be misunderstanding from my side. I should have
> > investigated this further before submitting the original patch. Sorry about
> > that.
> > 
> > Aaron,
> > 
> > Thanks for the investigation and pointing me to the right direction (e.g to
> > use acpi_video0 over the native one).
> 
> Could you check whether the ACPI video still really works even if you
> remove the recent acpi_osi blacklist entry below?  It might be that
> BIOS changed its mind to behave more kindly as if handling for Win7.
> 
> 
> Takashi
> 
> ---
> diff --git a/drivers/acpi/blacklist.c b/drivers/acpi/blacklist.c
> index 10e4964d051a..64d14406465d 100644
> --- a/drivers/acpi/blacklist.c
> +++ b/drivers/acpi/blacklist.c
> @@ -322,6 +322,7 @@ static struct dmi_system_id acpi_osi_dmi_table[] __initdata = {
>  		     DMI_MATCH(DMI_PRODUCT_VERSION, "2349D15"),
>  		},
>  	},
> +#if 0
>  	{
>  	.callback = dmi_disable_osi_win8,
>  	.ident = "HP ProBook 2013 models",
> @@ -372,6 +373,7 @@ static struct dmi_system_id acpi_osi_dmi_table[] __initdata = {
>  		     DMI_MATCH(DMI_PRODUCT_NAME, "HP EliteBook 8780w"),
>  		},
>  	},
> +#endif
>  
>  	/*
>  	 * BIOS invocation of _OSI(Linux) is almost always a BIOS bug.

After this patch is applied, the ACPI backlight doesn't work anymore. The
brightness stays the same, no matter what I do.