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

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Date:	Fri, 14 Feb 2014 15:54:51 +0100
From:	Takashi Iwai <tiwai@...e.de>
To:	Aaron Lu <aaron.lu@...el.com>
Cc:	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	linux-acpi@...r.kernel.org,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <lenb@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Revert "ACPI / video: Add HP EliteBook Revolve 810 to the blacklist"

At Fri, 14 Feb 2014 22:50:44 +0800,
Aaron Lu wrote:
> 
> On 02/14/2014 10:46 PM, Takashi Iwai wrote:
> > At Fri, 14 Feb 2014 16:45:24 +0200,
> > Mika Westerberg wrote:
> >>
> >> On Fri, Feb 14, 2014 at 03:16:58PM +0100, Takashi Iwai wrote:
> >>> At Fri, 14 Feb 2014 16:16:52 +0200,
> >>> Mika Westerberg wrote:
> >>>>
> >>>> On Fri, Feb 14, 2014 at 03:01:21PM +0100, Takashi Iwai wrote:
> >>>>> At Fri, 14 Feb 2014 16:03:16 +0200,
> >>>>> Mika Westerberg wrote:
> >>>>>>
> >>>>>> 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@...el.com>
> >>>>>>>> Signed-off-by: Mika Westerberg <mika.westerberg@...ux.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.
> >>>>>
> >>>>> So, you need the video blacklist when acpi_osi blacklist doesn't
> >>>>> exist, right?
> >>>>
> >>>> In my case I don't actually need video blacklist if I use only ACPI video
> >>>> for backlight control. Then it works fine.
> >>>
> >>> Hmm, after removing acpi_osi blacklist above, you loose the ACPI video
> >>> backlight doesn't work, no?  If so, you need the video blacklist.
> >>> Am I missing anything obvious...?
> >>
> >> Yes, the machine needs to be in acpi_osi blacklist then the ACPI video
> >> works fine.
> > 
> > The acpi_osi blacklist is just a workaround, and if we have better
> > solutions, it should be removed.  That's why I'm asking it.
> > 
> > So, after removing acpi_osi blacklist, and keeping your video
> > blacklist patch, the backlight works?  If yes, as mentioned, we should
> > think of rather extending this video blacklist to more EliteBook G1
> > and ProBook G1 machines, and remove acpi_osi blacklist instead.
> 
> Agree.
> 
> > 
> > Now hp-wireless is there, so the rfkill part should work without
> > acpi_osi blacklist, too.
> 
> Suppose we have some work around of making backlight work for
> them in Win8 mode, it seems the acpi_osi blacklist is ready to
> be removed now?

Once after confirming it really works ;)
I'll check other machines and report back in the next week.


Takashi
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