From: Matthew Garrett <matthew.garrett@nebula.com>
To: Aaron Lu <aaron.lu@intel.com>
Cc: Seth Forshee <seth.forshee@canonical.com>,
"daniel.vetter@ffwll.ch" <daniel.vetter@ffwll.ch>,
"intel-gfx@lists.freedesktop.org"
<intel-gfx@lists.freedesktop.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
"Rafael J. Wysocki" <rjw@sisk.pl>,
"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
"Lee, Chun-Yi" <joeyli.kernel@gmail.com>,
Alex Deucher <alexdeucher@gmail.com>,
Zhang Rui <rui.zhang@intel.com>, Aaron Lu <aaron.lwe@gmail.com>,
Len Brown <lenb@kernel.org>
Subject: Re: [PATCH 3/3] i915: Don't provide ACPI backlight interface if firmware expects Windows 8
Date: Sat, 15 Jun 2013 01:38:05 +0000 [thread overview]
Message-ID: <1371260284.523.2.camel@x230> (raw)
In-Reply-To: <51BBC2E1.9040401@intel.com>
On Sat, 2013-06-15 at 09:26 +0800, Aaron Lu wrote:
> On 06/15/2013 01:29 AM, Matthew Garrett wrote:
> > How would that work with existing userspace?
>
> User space tool will need to be updated to use this as stated in the
> gist page, I've patches for gsd-backlight-helper and xorg-x11-drv-intel,
> for others we can add I think if the priority based solution is deemed
> useful.
Right, that's not a great solution.
> > We shouldn't export interfaces if we don't expect them to work.
>
> It's not easy to decide if they work or not sometimes, e.g. I came
> across a system that claims win8 in ACPI table and has an Intel GPU,
> while its ACPI video interface also works. With this patch, the working
> ACPI video interface is removed, while with the priority based solution,
> the GPU's interface priority gets higher, but the ACPI video interface
> still stays.
Well, Windows 8 will only use the ACPI backlight interface if the GPU
driver decides to, right? So the logic for deciding whether to remove
the ACPI backlight control or not should be left up to the GPU. There's
no harm in refusing to expose a working method if there's another
working method, but there is harm in exposing a broken one and expecting
userspace to know the difference.
--
Matthew Garrett | mjg59@srcf.ucam.org
WARNING: multiple messages have this Message-ID (diff)
From: Matthew Garrett <matthew.garrett@nebula.com>
To: Aaron Lu <aaron.lu@intel.com>
Cc: "linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
Seth Forshee <seth.forshee@canonical.com>,
"Lee, Chun-Yi" <joeyli.kernel@gmail.com>,
"daniel.vetter@ffwll.ch" <daniel.vetter@ffwll.ch>,
"intel-gfx@lists.freedesktop.org"
<intel-gfx@lists.freedesktop.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Len Brown <lenb@kernel.org>, "Rafael J. Wysocki" <rjw@sisk.pl>,
Zhang Rui <rui.zhang@intel.com>, Aaron Lu <aaron.lwe@gmail.com>,
Alex Deucher <alexdeucher@gmail.com>
Subject: Re: [PATCH 3/3] i915: Don't provide ACPI backlight interface if firmware expects Windows 8
Date: Sat, 15 Jun 2013 01:38:05 +0000 [thread overview]
Message-ID: <1371260284.523.2.camel@x230> (raw)
In-Reply-To: <51BBC2E1.9040401@intel.com>
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 1457 bytes --]
On Sat, 2013-06-15 at 09:26 +0800, Aaron Lu wrote:
> On 06/15/2013 01:29 AM, Matthew Garrett wrote:
> > How would that work with existing userspace?
>
> User space tool will need to be updated to use this as stated in the
> gist page, I've patches for gsd-backlight-helper and xorg-x11-drv-intel,
> for others we can add I think if the priority based solution is deemed
> useful.
Right, that's not a great solution.
> > We shouldn't export interfaces if we don't expect them to work.
>
> It's not easy to decide if they work or not sometimes, e.g. I came
> across a system that claims win8 in ACPI table and has an Intel GPU,
> while its ACPI video interface also works. With this patch, the working
> ACPI video interface is removed, while with the priority based solution,
> the GPU's interface priority gets higher, but the ACPI video interface
> still stays.
Well, Windows 8 will only use the ACPI backlight interface if the GPU
driver decides to, right? So the logic for deciding whether to remove
the ACPI backlight control or not should be left up to the GPU. There's
no harm in refusing to expose a working method if there's another
working method, but there is harm in exposing a broken one and expecting
userspace to know the difference.
--
Matthew Garrett | mjg59@srcf.ucam.org
ÿôèº{.nÇ+‰·Ÿ®‰†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a¢f£¢·hšïêÿ‘êçz_è®\x03(階ŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨èÚ&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥
next prev parent reply other threads:[~2013-06-15 1:38 UTC|newest]
Thread overview: 108+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-09 23:01 [PATCH 0/3] Fix backlight issues on some Windows 8 systems Matthew Garrett
2013-06-09 23:01 ` [PATCH 1/3] acpi: video: add function to support unregister backlight interface Matthew Garrett
2013-06-09 23:01 ` [PATCH 2/3] ACPICA: Add interface for getting latest OS version requested via _OSI Matthew Garrett
2013-06-17 22:31 ` Rafael J. Wysocki
2013-06-17 22:37 ` Matthew Garrett
2013-06-17 22:37 ` Matthew Garrett
2013-06-18 0:42 ` Rafael J. Wysocki
2013-06-25 23:23 ` Rafael J. Wysocki
2013-07-02 13:56 ` [PATCH 0/2] Expose OSI version Aaron Lu
2013-07-02 13:59 ` [PATCH 1/2] ACPICA: expose " Aaron Lu
2013-07-02 14:01 ` [PATCH 2/2] ACPI / OSL: add a wrapper function to return " Aaron Lu
2013-07-03 21:57 ` Rafael J. Wysocki
2013-07-04 1:24 ` Aaron Lu
2013-07-05 19:52 ` Rafael J. Wysocki
2013-06-09 23:01 ` [PATCH 3/3] i915: Don't provide ACPI backlight interface if firmware expects Windows 8 Matthew Garrett
2013-06-10 7:40 ` Daniel Vetter
2013-06-10 9:22 ` joeyli
2013-06-10 14:09 ` Alex Deucher
2013-06-14 6:47 ` Aaron Lu
2013-06-14 17:29 ` Matthew Garrett
2013-06-14 17:29 ` Matthew Garrett
2013-06-15 1:26 ` Aaron Lu
2013-06-15 1:38 ` Matthew Garrett [this message]
2013-06-15 1:38 ` Matthew Garrett
2013-06-15 4:14 ` Aaron Lu
2013-06-15 4:14 ` Aaron Lu
2013-06-15 4:19 ` Matthew Garrett
2013-06-15 12:29 ` Aaron Lu
2013-06-15 12:29 ` Aaron Lu
2013-06-15 15:16 ` Matthew Garrett
2013-06-15 18:29 ` Daniel Vetter
2013-06-15 18:44 ` Matthew Garrett
2013-06-15 20:27 ` Rafael J. Wysocki
2013-06-15 20:35 ` Daniel Vetter
2013-07-05 12:20 ` Rafael J. Wysocki
2013-07-05 20:00 ` Rafael J. Wysocki
2013-07-05 21:40 ` Rafael J. Wysocki
2013-07-05 22:23 ` Rafael J. Wysocki
2013-07-06 5:45 ` Aaron Lu
2013-07-06 13:33 ` Rafael J. Wysocki
2013-07-07 13:19 ` Rafael J. Wysocki
2013-07-07 13:19 ` Rafael J. Wysocki
2013-07-08 8:00 ` Aaron Lu
2013-07-13 0:46 ` [Update][PATCH] ACPI / video / i915: Remove ACPI backlight " Rafael J. Wysocki
2013-07-15 2:36 ` Aaron Lu
2013-07-15 11:42 ` Rafael J. Wysocki
2013-07-16 3:24 ` Aaron Lu
2013-07-16 11:54 ` Rafael J. Wysocki
2013-07-15 13:06 ` Igor Gnatenko
2013-07-15 13:06 ` Igor Gnatenko
2013-07-15 23:53 ` Rafael J. Wysocki
2013-07-16 7:45 ` Igor Gnatenko
2013-07-16 7:45 ` Igor Gnatenko
2013-07-16 13:32 ` Igor Gnatenko
2013-07-16 13:32 ` Igor Gnatenko
2013-07-16 17:08 ` Matthew Garrett
2013-07-16 17:08 ` Matthew Garrett
2013-07-16 22:01 ` Rafael J. Wysocki
2013-07-17 5:16 ` Igor Gnatenko
2013-07-17 5:16 ` Igor Gnatenko
2013-07-17 11:38 ` Rafael J. Wysocki
2013-07-17 12:03 ` Igor Gnatenko
2013-07-17 12:03 ` Igor Gnatenko
2013-06-10 11:59 ` [PATCH 0/3] Fix backlight issues on some Windows 8 systems Rafael J. Wysocki
2013-06-10 13:48 ` Matthew Garrett
2013-06-10 13:48 ` Matthew Garrett
2013-06-11 13:08 ` Seth Forshee
2013-06-22 21:46 ` Yves-Alexis Perez
2013-06-25 16:08 ` Matthew Garrett
2013-06-25 16:10 ` Daniel Vetter
2013-06-25 16:13 ` Matthew Garrett
2013-06-25 20:43 ` Yves-Alexis Perez
2013-06-25 20:43 ` Yves-Alexis Perez
2013-06-25 20:54 ` Matthew Garrett
2013-06-25 21:10 ` Yves-Alexis Perez
2013-06-25 21:14 ` Matthew Garrett
2013-06-25 21:30 ` Yves-Alexis Perez
2013-06-25 21:33 ` Matthew Garrett
2013-06-25 21:33 ` Matthew Garrett
2013-06-25 21:46 ` Yves-Alexis Perez
2013-06-25 21:49 ` Matthew Garrett
2013-06-25 21:49 ` Matthew Garrett
2013-07-17 15:51 ` Felipe Contreras
2013-07-17 19:57 ` Yves-Alexis Perez
2013-07-18 0:16 ` [Update][PATCH " Rafael J. Wysocki
2013-07-18 0:20 ` [PATCH 1/3] ACPICA: expose OSI version Rafael J. Wysocki
2013-07-18 5:38 ` Igor Gnatenko
2013-07-18 5:38 ` Igor Gnatenko
2013-07-18 0:21 ` [PATCH 2/3] ACPI / video: Always call acpi_video_init_brightness() on init Rafael J. Wysocki
2013-07-18 5:40 ` Igor Gnatenko
2013-07-18 5:40 ` Igor Gnatenko
2013-07-18 0:22 ` [PATCH 3/3] ACPI / video / i915: No ACPI backlight if firmware expects Windows 8 Rafael J. Wysocki
2013-07-20 13:16 ` [Update][PATCH 0/3] Fix backlight issues on some Windows 8 systems Felipe Contreras
2013-07-26 13:24 ` Jani Nikula
2013-07-29 18:01 ` Felipe Contreras
2013-07-30 5:03 ` Jani Nikula
2013-07-31 0:01 ` Rafael J. Wysocki
2013-07-31 0:01 ` Matthew Garrett
2013-07-31 0:01 ` Matthew Garrett
2013-07-31 6:48 ` Igor Gnatenko
2013-07-31 6:48 ` Igor Gnatenko
2013-07-31 9:08 ` Aaron Lu
2013-08-07 7:44 ` Backlight control only in the kernel? Borislav Petkov
2013-08-07 9:03 ` Aaron Lu
2013-08-07 10:34 ` Borislav Petkov
2013-08-07 10:36 ` Matthew Garrett
2013-08-07 10:36 ` Matthew Garrett
2013-08-07 11:04 ` Borislav Petkov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1371260284.523.2.camel@x230 \
--to=matthew.garrett@nebula.com \
--cc=aaron.lu@intel.com \
--cc=aaron.lwe@gmail.com \
--cc=alexdeucher@gmail.com \
--cc=daniel.vetter@ffwll.ch \
--cc=dri-devel@lists.freedesktop.org \
--cc=intel-gfx@lists.freedesktop.org \
--cc=joeyli.kernel@gmail.com \
--cc=lenb@kernel.org \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=rjw@sisk.pl \
--cc=rui.zhang@intel.com \
--cc=seth.forshee@canonical.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.