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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri, 14 Feb 2014 15:46:20 +0100
From:	Takashi Iwai <tiwai@...e.de>
To:	Mika Westerberg <mika.westerberg@...ux.intel.com>
Cc:	linux-acpi@...r.kernel.org,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <lenb@...nel.org>, Aaron Lu <aaron.lu@...el.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Revert "ACPI / video: Add HP EliteBook Revolve 810 to the blacklist"

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.

Now hp-wireless is there, so the rfkill part should work without
acpi_osi blacklist, too.


Takashi
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/