Bug 29685

Summary:

DPMS does not turn off LCD backlight on NV18 [GeForce4 MX with AGP8X (Mac)]

Product:

xorg

Reporter:

Vlado Plaga <rechner>

Component:

Driver/nouveau

Assignee:

Nouveau Project <nouveau>

Status:

RESOLVED FIXED

QA Contact:

Xorg Project Team <xorg-team>

Severity:

normal

Priority:

medium

Version:

7.5 (2009.10)

Hardware:

PowerPC

OS:

Linux (All)

Whiteboard:

i915 platform:

i915 features:

Attachments:

Description	Flags
nouveau_imac_backlight.patch	none

Description Vlado Plaga 2010-08-19 23:50:33 UTC

I'm using bug #19356, which describes the same problem with a different iMac, as an orientation for my bug description.

Expected:
$ xset dpms force standby;
should turn off LCD backlight.

Actual Result:
Screen is black, but LCD backlight stays on.

Workaround:
Use nv driver.

Some information on my system is already in bug #29455 (video bios dump, register dump, "lspci -vvnn" output).

I downloaded, compiled, and ran radeontool, as was described in bug #19356:

nouveau driver:

DPMS on:
0x0060081c      0xa2565051 (-1571401647)
0x000010f0      0x84830535 (-2071788235)
DPMS off:
0x0060081c      0xa2565055 (-1571401643)
0x000010f0      0x84830535 (-2071788235)

nv driver:

DPMS on:
0x0060081c      0xa2565051 (-1571401647)
0x000010f0      0x84550535 (-2074802891)
DPMS off:
0x0060081c      0xa2565050 (-1571401648)
0x000010f0      0x04550535 (72680757)

Comment 1 Francisco Jerez 2010-08-20 05:35:50 UTC

Created attachment 38013 [details] [review]
nouveau_imac_backlight.patch

The attached patch should fix it, can you give it a try?

Comment 2 Vlado Plaga 2010-08-21 04:59:32 UTC

(In reply to comment #1)

> The attached patch should fix it, can you give it a try?

Yes! Great! Thank you! Now for me nouveau is superior to nv in every aspect... except for "installation", maybe. ;-)

First I tried the patch with Ubuntu 10.10's kernel sources (2.6.35), and it was applied without complaint, but the compilation failed with

drivers/gpu/drm/nouveau/nv04_dfp.c: In function ‘nv04_dfp_update_backlight’:
drivers/gpu/drm/nouveau/nv04_dfp.c:454: error: implicit declaration of function ‘nv_mask’
make[5]: *** [drivers/gpu/drm/nouveau/nv04_dfp.o] Fehler 1
make[4]: *** [drivers/gpu/drm/nouveau] Fehler 2
make[3]: *** [drivers/gpu/drm] Fehler 2
make[2]: *** [drivers/gpu] Fehler 2
make[1]: *** [drivers] Fehler 2
make[1]: Verlasse Verzeichnis '/usr/src/linux-source-2.6.35'
make: *** [debian/stamp/build/kernel] Fehler 2

Then I tried the official 2.6.36-rc1, and the backlight can now be switched off properly. Unfortunately the EDID error mentioned in bug #29455 is also back again.

Will that bug be fixed in 2.6.36-rc2? Can I just replace the "gpu/drm/nouveau" directory? Or should I take the whole linux tree from nouveau's git again?

Comment 3 Francisco Jerez 2010-08-21 14:45:01 UTC

(In reply to comment #2)
> (In reply to comment #1)
> 
> > The attached patch should fix it, can you give it a try?
> 
> Yes! Great! Thank you! Now for me nouveau is superior to nv in every aspect...
> except for "installation", maybe. ;-)
> 
Ok, pushed.

> First I tried the patch with Ubuntu 10.10's kernel sources (2.6.35), and it was
> applied without complaint, but the compilation failed with
> 
> drivers/gpu/drm/nouveau/nv04_dfp.c: In function ‘nv04_dfp_update_backlight’:
> drivers/gpu/drm/nouveau/nv04_dfp.c:454: error: implicit declaration of function
> ‘nv_mask’
> make[5]: *** [drivers/gpu/drm/nouveau/nv04_dfp.o] Fehler 1
> make[4]: *** [drivers/gpu/drm/nouveau] Fehler 2
> make[3]: *** [drivers/gpu/drm] Fehler 2
> make[2]: *** [drivers/gpu] Fehler 2
> make[1]: *** [drivers] Fehler 2
> make[1]: Verlasse Verzeichnis '/usr/src/linux-source-2.6.35'
> make: *** [debian/stamp/build/kernel] Fehler 2
> 
49eed80ad0cfa5d5d02992e8088463cbf1a5ff85 is what you're missing.

> Then I tried the official 2.6.36-rc1, and the backlight can now be switched off
> properly. Unfortunately the EDID error mentioned in bug #29455 is also back
> again.
> 
Try cherry-picking c80da92edec995a39afe2a8c2ede2fe2e2b30fc0 from the nouveau kernel tree.

> Will that bug be fixed in 2.6.36-rc2?

Not sure if it will be fixed for RC2 but it will probably be for one of the next RCs.

> Can I just replace the "gpu/drm/nouveau"
> directory? Or should I take the whole linux tree from nouveau's git again?

That works sometimes, if the internal APIs haven't been broken between the kernel versions you're trying to mix, but no guarantees.

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