[i945] [i945] [karmic] regression: I can't turn off LVDS on my MSI Wind (Intel 945GME)

[boskicinek]

Hi!
It's seems that I'm unable to turn off LVDS on my MSI Wind. What's weird is a fact, that I'm using my Wind with external monitor (VGA1) and, when LVDS1 is disabled, screen suspend works (on VGA1).
This bug is easy to reproduce:
$ xrandr
Screen 0: minimum 320 x 200, current 1440 x 900, maximum 4096 x 4096
VGA1 connected 1440x900+0+0 (normal left inverted right x axis y axis) 408mm x 255mm
   1440x900 59.9*+ 59.9*
   1280x1024 75.0
   1152x864 75.0
   1024x768 75.1 70.1 60.0 60.0
   832x624 74.6
   800x600 75.0 60.3 56.2
   640x480 75.0 60.0
   720x400 70.1
LVDS1 connected 1024x600+0+0 (normal left inverted right x axis y axis) 220mm x 129mm
   1024x600 60.0*+
   640x480 59.9

$ xset dpms force off
[This turns off both screens for 1 second and then automatically turns it back on - without any trace in dmesg]

$ xrandr --output LVDS1 --off
$ xset dpms force off
[And now everything works as expected]

I can provide more information on this, if needed. Just tell me what you need.

[lspci]
00:00.0 Host bridge [0600]: Intel Corporation Mobile 945GME Express Memory Controller Hub [8086:27ac] (rev 03)
     Subsystem: Micro-Star International Co., Ltd. Device [1462:0110]
00:02.0 VGA compatible controller [0300]: Intel Corporation Mobile 945GME Express Integrated Graphics Controller [8086:27ae] (rev 03)
     Subsystem: Micro-Star International Co., Ltd. Device [1462:0110]

[Bryce Harrington (bryce)]

Hi boski-cinek,

Please attach the output of `lspci -vvnn` and `dmesg`, and attach your /var/log/Xorg.0.log (and maybe Xorg.0.log.old) file from after reproducing this issue. If you're using a custom /etc/X11/xorg.conf please attach that as well.

[This is an automated message. Apologies if it has reached you inappropriately; please just reply to this message indicating so.]

[boskicinek (boski-cinek)]

I'm not attaching dmesg output, because, as I said, this issue doesn't produce any output in dmesg.

[Alexpro (alexpro)]

I have MSI Wind U100 netbook (945GM chipset). After upgrading driver
to 2.9.x DPMS stopped working in xorg: screen just blinks and stays in "on" state.

I've found that this problem is caused by driver setting brightness to 0 when
setting DPMS level (src/drmmode_display.c:925) via kernel backlight driver.
And on my system writing to /sys/devices/backlight/acpi_video0/brightness generates keypress events (as if I pressed brightness controls on keyboard). This keypresses immediately wake x server.

Simplest fix is to remove drmmode_output_dpms_backlight call.

Actually, I'm not sure if this "feature" should be filed here. Maybe this should be corrected in kernel. But it seems it is easier to correct in xorg driver.

BTW, in non-KMS mode this problem also exists but can be easily repaired by setting BACKLIGHT_CONTROL to 'native' with xrandr.

Kernel version: 2.6.31
Xorg version: 1.7.1
Intel driver version: 2.9.1

[Carl Worth (cworth)]

I'll assign this to Jesse.

I'm guessing that he'll know the proper fix, (or at least know the person
who should know that).

-Carl

[Guido+freedesktop-org (guido+freedesktop-org)]

A few more details on this can be found on the Ubuntu bugtracker: https://bugs.launchpad.net/xserver-xorg-video-intel/+bug/453812

[Guido Berhoerster (gber)]

Adding dmesg output, I have the same hardware and same problem.

[Guido Berhoerster (gber)]

Just for reference, the problem here is that the MSI Wind UXXX and its OEM variants generate keypress events in hardware each time the brightness level is changed which is a source of trouble (e.g. see bug #415023). Since the Intel Xorg driver sets the brightness to 0 before turning the screen off via DPMS, keypress events are generated which cause power management software such as gnome-power-manaager, powerdevil, or xfce4-power-manager to immediately turn it back on. the details are in the upstream bug.

[Jesse Barnes (jbarnes-virtuousgeek)]

Does this still happen with 2.6.33-rc kernels and the 2.10 X driver?

[yakuizhao (yakui-zhao)]

Hi, Alex
    Sorry for the late response.
    Do you try to remove the remove drmmode_output_dpms_backlight call in drmmode_output_dpms and see whether the issue can be fixed?
    It seems that we use the incorrect order to set the backlight brightness. When the LVDS enters the DPMS off set, we will use the kernel syscall to put it into DPMS off set and then read the backlight brightness setting(In fact it will be the lowest). When we put it into DPMS on state again, it will then use the kernel syscall and then restore the saved backlight brightness setting. It is incorrect.

     Please check whether it can work for you if you remove the drmmode_output_dpms_backlight call in drmmode_output_dpms.

thanks.
    Yakui

[Alexpro (alexpro)]

Hi,

I am currently not using latest kernel - mine is 2.6.32 (with gentoo patchset).
Intel driver is quite up-to-date - 2.10.0.
To make DPMS work, I've commented "drmmode_output_dpms_backlight" call in drmmode_output_dpms.

So yes, commenting drmmode_output_dpms_backlight works.

[yakuizhao (yakui-zhao)]

HI, Alex
    Can you send the corresponding patch to intel-gfx mailing list? And then I can add the "Acked-by".

thanks.
    Yakui

[Gordon Jin (gordon-jin)]

Let's not hold here.

Yakui, could you send/commit the patch if Alex doesn't do that?

[Guido+freedesktop-org (guido+freedesktop-org)]

On my MSI Wind U100 I cannot reproduce this any more after upgrading the BIOS to version 1.0G.

[Alexpro (alexpro)]

I've just upgraded BIOS to 1.0g on my U100 and can confirm:
this bug dissapeared.

[Mhopf-suse (mhopf-suse)]

Removing drmmode_output_dpms_backlight is certainly not the right solution. As long as there is a BIOS update that fixes this issue I'd suggest to not change that part of code.

It's especially prone to break power saving for older laptop models that don't have dedicated hardware for switching off the backlight if the panel doesn't get a valid signal.

[Sndirsch-suse (sndirsch-suse)]

I agree with Matthias. Apparently that's a BIOS bug. Hence closing accordingly.

[bugbot (bugbot)]

This bug report was filed against an old version of Ubuntu.
Can you confirm whether this is still an issue in natty?

Please also ensure this bug has tags for each Ubuntu release
that the bug is confirmed as affecting.

[Chris Wilson (ickle)]

Determined to be a BIOS bug.