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Date:	Wed, 17 Nov 2010 11:16:50 +0800
From:	Zhang Rui <rui.zhang@...el.com>
To:	Joey Lee <jlee@...ell.com>
Cc:	"mingo@...e.hu" <mingo@...e.hu>,
	"lenb@...nel.org" <lenb@...nel.org>,
	"airlied@...hat.com" <airlied@...hat.com>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH]  do not select ACPI_VIDEO in poulsbo stub driver

On Wed, 2010-11-17 at 11:04 +0800, Joey Lee wrote:
> Hi Rui, 
> 
> 於 三,2010-11-17 於 08:42 +0800,Zhang Rui 提到:
> > On Tue, 2010-11-16 at 15:34 +0800, Joey Lee wrote:
> > > Hi Rui, 
> > > 
> > > Sorry about this patch will not work on my MSi poulsbo machine.
> > > 
> > > 於 二,2010-11-16 於 14:04 +0800,Zhang Rui 提到:
> > > > the poulsbo stub driver should not select ACPI video driver.
> > > > 
> > > > The reason why i915 driver selects ACPI video driver is that it needs some
> > > > cooperation between these two drivers during initialization, or else the
> > > > system may hang.
> > > > 
> > > > So if users want ACPI backlight control, please set CONFIG_ACPI_VIDEO manually.
> > > > 
> > > > http://marc.info/?l=linux-acpi&m=128952659018533&w=2
> > > > 
> > > > CC: Ingo Molnar <mingo@...e.hu>
> > > > CC: Dave Airlie <airlied@...hat.com>
> > > > CC: Lee, Chun-Yi <joeyli.kernel@...il.com>
> > > > Signed-off-by: Zhang Rui <rui.zhang@...el.com>
> > > > ---
> > > >  drivers/gpu/stub/Kconfig   |   11 +----------
> > > >  drivers/gpu/stub/poulsbo.c |    5 +----
> > > >  2 files changed, 2 insertions(+), 14 deletions(-)
> > > > 
> > > > Index: linux-2.6/drivers/gpu/stub/Kconfig
> > > > ===================================================================
> > > > --- linux-2.6.orig/drivers/gpu/stub/Kconfig
> > > > +++ linux-2.6/drivers/gpu/stub/Kconfig
> > > > @@ -1,16 +1,7 @@
> > > >  config STUB_POULSBO
> > > >  	tristate "Intel GMA500 Stub Driver"
> > > >  	depends on PCI
> > > > -	# Poulsbo stub depends on ACPI_VIDEO when ACPI is enabled
> > > > -	# but for select to work, need to select ACPI_VIDEO's dependencies, ick
> > > > -	select VIDEO_OUTPUT_CONTROL if ACPI
> > > > -	select BACKLIGHT_CLASS_DEVICE if ACPI
> > > > -	select INPUT if ACPI
> > > > -	select ACPI_VIDEO if ACPI
> > > >  	help
> > > >  	  Choose this option if you have a system that has Intel GMA500
> > > >  	  (Poulsbo) integrated graphics. If M is selected, the module will
> > > > -	  be called Poulsbo. This driver is a stub driver for Poulsbo that
> > > > -	  will call poulsbo.ko to enable the acpi backlight control sysfs
> > > > -	  entry file because there have no poulsbo native driver can support
> > > > -	  intel opregion.
> > > > +	  be called Poulsbo.
> > > > Index: linux-2.6/drivers/gpu/stub/poulsbo.c
> > > > ===================================================================
> > > > --- linux-2.6.orig/drivers/gpu/stub/poulsbo.c
> > > > +++ linux-2.6/drivers/gpu/stub/poulsbo.c
> > > > @@ -11,8 +11,6 @@
> > > >  
> > > >  #include <linux/module.h>
> > > >  #include <linux/pci.h>
> > > > -#include <linux/acpi.h>
> > > > -#include <acpi/video.h>
> > > >  
> > > >  #define DRIVER_NAME "poulsbo"
> > > >  
> > > > @@ -29,12 +27,11 @@ static DEFINE_PCI_DEVICE_TABLE(pciidlist
> > > >  
> > > >  static int poulsbo_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> > > >  {
> > > > -	return acpi_video_register();
> > > > +	return 0;
> > > >  }
> > > 
> > > Sorry, we cann't remove to call acpi_video_register, because the acpi
> > > video will not generate because there have some poulsbo machine declare
> > > Intel opregion in DSDT but the i915 driver not support poulsbo.
> > > 
> > I'm confused.
> > It's the i915 driver that supports Intel Opregion.
> > i.e. for a poulsbo machine with Intel Opregion, loading ACPI video
> > driver won't help neither.
> > 
> 
> Matthew have a patch:
> 
>       * http://git.kernel.org/?p=linux/kernel/git/lenb/linux-acpi-2.6.git;a=commitdiff;h=74a365b3f354fafc537efa5867deb7a9fadbfe27
> 
> This patch do:
> 
> - ACPI video driver will not register if it check the DSDT have opregion table declare.
> - i915_opregion will call acpi_video_register after it initialised the DIDL field in opregion.
> 
> That means acpi video driver will blocked when have opregion declare in
> DSDT until i915 drm driver call acpi_video_register. The patch fixed
> BKO#11259, but introduced a side effect: If there have Intel video chip
> not supported by Intel drm driver, the acpi_video_register will never
> called, then some machine have good acpi backlight interface
> implementation will never have acpi brightness sysfs interface for
> userland control. e.g. any Poulsbo netbook.
> 
> Matthew's comment to talk about the side effect: Intel IGD opregion and
> GMA500
> 
> There have some machines declare opregion in DSDT but they also
> implement the backlight control by EC in _BCM. Like: MSI poulsbo
> netbook.
> Before introduce the above patch to kernel, those machine's acpi
> backlight control works fine. On current kernel, those machines
> backlight control broken.
> 
> One function workable with old kernel but broken by new kernel, now.
> 
Oh, I see what the problem is.
You're right, this patch doesn't make sense. Sorry for the noise. :)

thanks,
rui

> 
> > > That's why we add the poulsbo stub driver to enable the acpi video
> > > because those machine implement acpi _BCL, _BCM interace and control
> > > brightness by ec.
> > 
> > I got your idea.
> > I'm not sure if this is right. IMO, the graphics driver and ACPI video
> > driver are independent. I mean, to enable the ACPI backlight control,
> > users should set CONFIG_ACPI_VIDEO explicitly.
> > 
> > And again, the reason why i915 driver selects ACPI_VIDEO is that the
> > i915 Opregion code must run *before* ACPI video driver loaded, or else
> > system hangs on some machines.
> > and the reason why DRM_NOUVEAU selects ACPI_VIDEO is that it depends on
> > ACPI to get the EDID info.
> > 
> 
> Yes, Matthew's patch fix this issue. 
> 
> > So I don't see a strong reason that STUB_POULSBO should select
> > ACPI_VIDEO.
> > 
> 
> Does it possible we direct remove the "select ACPI_VIDEO if ACPI" from
> Kconfig but keep the acpi_video_register function call in stub poulsbo
> driver?
> Because acpi/video.h already handle the ACPI VIDEO config check:
> 
> #if (defined CONFIG_ACPI_VIDEO || defined CONFIG_ACPI_VIDEO_MODULE)
> extern int acpi_video_register(void);
> extern void acpi_video_unregister(void);
> extern int acpi_video_get_edid(struct acpi_device *device, int type,
>                                int device_id, void **edid);
> #else
> static inline int acpi_video_register(void) { return 0; }
> static inline void acpi_video_unregister(void) { return; }
> 
> 
> Thank's a lot!
> Joey Lee
> 
> > thanks,
> > rui
> > > 
> > > Here is our discussion:
> > > 	http://www.spinics.net/lists/linux-acpi/msg30027.html
> > > 
> > > >  
> > > >  static void poulsbo_remove(struct pci_dev *pdev)
> > > >  {
> > > > -	acpi_video_unregister();
> > > >  }
> > > >  
> > > >  static struct pci_driver poulsbo_driver = {
> > > > 
> > > > 
> > > 
> > > I am sorry I miss understand your last mail for poulsbo stub driver
> > > cann't dependency on input, because your patch is old.
> > > 
> > > The following is the newest patch that was send out by me:
> > > 
> > > 
> > > >From 340b1068b20cfa152ff9992a7d69d19501b57163 Mon Sep 17 00:00:00 2001
> > > From: Lee, Chun-Yi <jlee@...ell.com>
> > > Date: Wed, 15 Sep 2010 22:19:25 +0800
> > > Subject: [PATCH] Add Intel GMA500(Poulsbo) Stub Driver
> > > 
> > > Currently, there have no GMA500(Poulsbo) native video driver to support
> > > intel opregion. So, use this stub driver to enable the acpi backlight
> > > control sysfs entry files by requrest acpi_video_register.
> > > 
> > > Signed-off-by: Lee, Chun-Yi <jlee@...ell.com>
> > > ---
> > >  drivers/gpu/Makefile       |    2 +-
> > >  drivers/gpu/stub/Kconfig   |   13 +++++++++
> > >  drivers/gpu/stub/Makefile  |    1 +
> > >  drivers/gpu/stub/poulsbo.c |   63 ++++++++++++++++++++++++++++++++++++++++++++
> > >  drivers/video/Kconfig      |    2 +
> > >  5 files changed, 80 insertions(+), 1 deletions(-)
> > >  create mode 100644 drivers/gpu/stub/Kconfig
> > >  create mode 100644 drivers/gpu/stub/Makefile
> > >  create mode 100644 drivers/gpu/stub/poulsbo.c
> > > 
> > > diff --git a/drivers/gpu/Makefile b/drivers/gpu/Makefile
> > > index 30879df..cc92778 100644
> > > --- a/drivers/gpu/Makefile
> > > +++ b/drivers/gpu/Makefile
> > > @@ -1 +1 @@
> > > -obj-y			+= drm/ vga/
> > > +obj-y			+= drm/ vga/ stub/
> > > diff --git a/drivers/gpu/stub/Kconfig b/drivers/gpu/stub/Kconfig
> > > new file mode 100644
> > > index 0000000..8f5a540
> > > --- /dev/null
> > > +++ b/drivers/gpu/stub/Kconfig
> > > @@ -0,0 +1,13 @@
> > > +config STUB_POULSBO
> > > +	tristate "Intel GMA500 Stub Driver"
> > > +	depends on> > +        # Poulsbo stub depends on ACPI_VIDEO when ACPI is enabled
> > > +        # but for select to work, need to select ACPI_VIDEO's dependencies, ick
> > > +        select ACPI_VIDEO if ACPI
> > > +	help
> > > +	  Choose this option if you have a system that has Intel GMA500
> > > +	  (Poulsbo) integrated graphics. If M is selected, the module will
> > > +	  be called Poulsbo. This driver is a stub driver for Poulsbo that
> > > +	  will call poulsbo.ko to enable the acpi backlight control sysfs
> > > +	  entry file because there have no poulsbo native driver can support
> > > +	  intel opregion.
> > > diff --git a/drivers/gpu/stub/Makefile b/drivers/gpu/stub/Makefile
> > > new file mode 100644
> > > index 0000000..cd940cc
> > > --- /dev/null
> > > +++ b/drivers/gpu/stub/Makefile
> > > @@ -0,0 +1 @@
> > > +obj-$(CONFIG_STUB_POULSBO) += poulsbo.o
> > > diff --git a/drivers/gpu/stub/poulsbo.c b/drivers/gpu/stub/poulsbo.c
> > > new file mode 100644
> > > index 0000000..d8aa636
> > > --- /dev/null
> > > +++ b/drivers/gpu/stub/poulsbo.c
> > > @@ -0,0 +1,63 @@
> > > +/*
> > > + * Intel Poulsbo Stub driver
> > > + *
> > > + * Copyright (C) 2010 Novell <jlee@...ell.com>
> > > + *
> > > + * This program is free software; you can redistribute it and/or modify it
> > > + * under the terms of the GNU General Public License version 2 as published by
> > > + * the Free Software Foundation.
> > > + *
> > > + */
> > > +
> > > +#include <linux/module.h>
> > > +#include <linux/pci.h>
> > > +#include <acpi/video.h>
> > > +
> > > +#define DRIVER_NAME "poulsbo"
> > > +
> > > +enum {
> > > +	CHIP_PSB_8108 = 0,
> > > +	CHIP_PSB_8109 = 1,
> > > +};
> > > +
> > > +static struct pci_device_id pciidlist[] = {
> > > +	{0x8086, 0x8108, PCI_ANY_ID, PCI_ANY_ID, 0, 0, CHIP_PSB_8108}, \
> > > +	{0x8086, 0x8109, PCI_ANY_ID, PCI_ANY_ID, 0, 0, CHIP_PSB_8109}, \
> > > +	{0, 0, 0}
> > > +};
> > > +
> > > +static int poulsbo_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> > > +{
> > > +	return acpi_video_register();
> > > +}
> > > +
> > > +static void poulsbo_remove(struct pci_dev *pdev)
> > > +{
> > > +	acpi_video_unregister();
> > > +}
> > > +
> > > +static struct pci_driver poulsbo_driver = {
> > > +	.name = DRIVER_NAME,
> > > +	.id_table = pciidlist,
> > > +	.probe = poulsbo_probe,
> > > +	.remove = poulsbo_remove,
> > > +};
> > > +
> > > +static int __init poulsbo_init(void)
> > > +{
> > > +	return pci_register_driver(&poulsbo_driver);
> > > +}
> > > +
> > > +static void __exit poulsbo_exit(void)
> > > +{
> > > +	pci_unregister_driver(&poulsbo_driver);
> > > +}
> > > +
> > > +module_init(poulsbo_init);
> > > +module_exit(poulsbo_exit);
> > > +
> > > +MODULE_AUTHOR("Lee, Chun-Yi <jlee@...ell.com>");
> > > +MODULE_DESCRIPTION("Poulsbo Stub Driver");
> > > +MODULE_LICENSE("GPL");
> > > +
> > > +MODULE_DEVICE_TABLE(pci, pciidlist);
> > > diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
> > > index 8b31fdf..8807ae5 100644
> > > --- a/drivers/video/Kconfig
> > > +++ b/drivers/video/Kconfig
> > > @@ -17,6 +17,8 @@ source "drivers/gpu/vga/Kconfig"
> > >  
> > >  source "drivers/gpu/drm/Kconfig"
> > >  
> > > +source "drivers/gpu/stub/Kconfig"
> > > +
> > >  config VGASTATE
> > >         tristate
> > >         default n
> > 
> > 
> 


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