Re: [PATCH] do not select ACPI_VIDEO in poulsbo stub driver

[Zhang Rui <rui.zhang@intel.com>]

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@elte.hu>
> > CC: Dave Airlie <airlied@redhat.com>
> > CC: Lee, Chun-Yi <joeyli.kernel@gmail.com>
> > Signed-off-by: Zhang Rui <rui.zhang@intel.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.

> 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.

So I don't see a strong reason that STUB_POULSBO should select
ACPI_VIDEO.

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@novell.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@novell.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 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 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@novell.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@novell.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