linux-kernel - Re: [PATCH] Add intel drm blacklist to intel_opregion

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Date:	Mon, 12 Jul 2010 09:12:13 -0600
From:	"Joey Lee" <jlee@...ell.com>
To:	<mjg59@...f.ucam.org>
Cc:	<dri-devel@...ts.sourceforge.net>, <linux-acpi@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <Dennis.Jansen@....de>
Subject: Re: [PATCH] Add intel drm blacklist to intel_opregion_present
 detect

Hi Mattew, 

於 一，2010-07-12 於 03:27 +0100，Matthew Garrett 提到：
> On Sun, Jul 11, 2010 at 08:12:57PM -0600, Joey Lee wrote:
> 
> > He tested the drm blacklist patch can works fine on his computer, it's
> > also works on VESA mode because the acpi _BCM, _BQC direct change
> > brightness by opregion.
> > 

Sorry, I write a wrong information, the MSI poulsbo netbook change
brightness by ec command in _BCM, _BQC, not opregion.

> > What can we do for this situtation? I mean if the BIOS have opregion
> > implementation but there have no opensource drm driver or native video
> > driver support opregion on Linux?
> 
> The cleanest way would be to implement a stub backlight control driver 
> for the chip - there should be enough information in the source of the 
> poulsbo drm to do that. 

M... Follow your suggestion, I am tracing the i915 drm driver and
Poulsbo drm driver from here:

http://sourceforge.net/mailarchive/message.php?msg_name=49C2ADA8.2090405%40shipmail.org

I am not sure fully understood your suggestion... Did you mean we can
extract some parts from Poulsbo drm driver and put it to a stub
backlight control driver for Poulsbo? Where can we put the stub driver?
Do we still put it in i915 drm? 

On the other hand, the Poulsbo is a old and stop ship chip, do we still
want to add a special driver for it?

> The main problem with the blacklist approach is 
> that there's no guarantee that all poulsbo systems will have a working 
> acpi method, and I /think/ there's a couple more PCI IDs that ought to 
> be covered in any case. On the other hand doing it properly does involve 
> writing rather a lot more code, and the fact that Intel have shown 
> absolutely no interest in making their hardware work means that the 
> quick hack might be the most reasonable thing to do.
> 

Thank's for your remind, I fully agreed cann't guarantee all poulsbo
systems have working acpi method. But, I am sure the MSI U110/U115 have
workable acpi backlight method.
Do you think it's good to put the special DMI detection in msi-laptop
driver to enable the the acpi backlight control by call
acpi_video_register in acpi video? But will cause msi-laptop driver
dependency to acpi video driver.

Need your kindly suggestion!

Thank's a lot!
Joey Lee

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