Re: [Regression] Laptop screen dark when lid closed and reopened.with 3.1

[Alex Davis <alex14641@yahoo.com>]

>From: Keith Packard <keithp@keithp.com>
>To: Alex Davis <alex14641@yahoo.com>; "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
>Cc:
>Sent: Saturday, September 24, 2011 1:40 PM
>Subject: Re: [Regression] Laptop screen dark when lid closed and reopened.with 3.1
>
>On Sat, 24 Sep 2011 08:13:42 -0700 (PDT), Alex Davis <alex14641@yahoo.com> wrote:
>
>> One good thing about the 3.1 kernels is that I now have the /sys/class/backlight/intel_backlight directory
>> in addition to /sys/class/backlight/dell_backlight. With intel_backlight, I can control the LCD brightness;
>> dell_backlight never worked, neither in 3.0 or 3.1.
>
>Can you tell if the screen is blank with the backlight on, or is the
>screen drawn correctly and the backlight off?
>
>If the screen is blank but the backlight is on, then you may want a
>patch which is on my drm-intel-fixes branch.
>
>git://anongit.freedesktop.org/~keithp/linux
>
>If the screen is drawn, but the backlight is off, you may want to try
>reverting the native backlight patch:
>
>aaa6fd2a004147bf32fce05720938236de3361d9
>
>Author: Matthew Garrett <mjg@redhat.com>  2011-08-12 03:11:33
>Committer: Keith Packard <keithp@keithp.com>  2011-08-15 12:10:25
>Parent: 302983e9059e9ef5de3ca7671918eeb237c5971e (drm/i915/pch: Fix integer math bugs in panel fitting)
>
>Not all systems expose a firmware or platform mechanism for changing the backlight intensity on i915, so add native driver support.
>
>-- 
>keith.packard@intel.com

Action: close lid, open lid, and press return key.

Result with 3.0.x: password dialog appears. This is the correct result.

Result with git://anongit.freedesktop.org/~keithp/linux: screen is dark.
Manually adjusting the brightness reveals a functioning mouse cursor, but
no password dialog. Switching to a text console and back to the X session
reveals the dialog.

Result with 3.1rc7 with aaa6fd2a004147bf32fce05720938236de3361d9 reverted:
screen with a functioning mouse cursor, but no password dialog. Switching
to a text console and back to the X session reveals the dialog. Brightness
cannot be controlled.