Patchwork i915/kms/backlight-combo mode problem (was: Re: Linux 2.6.39-rc5)

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Submitter Takashi Iwai
Date April 30, 2011, 10:27 a.m.
Message ID <s5hiptwavar.wl%tiwai@suse.de>
Download mbox | patch
Permalink /patch/743162/
State New, archived
Headers show

Comments

Takashi Iwai - April 30, 2011, 10:27 a.m.
At Sat, 30 Apr 2011 10:32:04 +0200,
Melchior FRANZ wrote:
> 
> * Takashi Iwai -- Saturday 30 April 2011:
> > I remember vaguely that the value zero could be interpreted as the max.
> 
> > Also, with the patch, does the backlight level can be adjusted
> > correctly to different values?  I wonder whether LBPC adjustment
> > really works or not on your machine.
> 
> > +			if (!lbpc)
> > +				lbpc = 0xff; /* max value */
> 
> This change does *not* work on my machine. The screen stays black
> again.

Hrm, then it's really hard to say how exactly the system behaves when
lbpc=0...  I guess we should avoid controlling LBPC in such a case,
e.g. something like the patch below (totally untested).

But Intel guys must know of this better... I leave this to their
hands.

> 
> Yes, backlight adjustment generally works on this notebook, but only
> with "acpi_osi=Linux" on the command line.

acpi_osi quirk should be better added statically, then.


thanks,

Takashi

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Melchior FRANZ - April 30, 2011, 11:34 a.m.
Dropping Linus from the CC.


* Takashi Iwai -- Saturday 30 April 2011:
* * At Sat, 30 Apr 2011 10:32:04 +0200, Melchior FRANZ wrote:
> > Yes, backlight adjustment generally works on this notebook, but only
> > with "acpi_osi=Linux" on the command line.
> 
> acpi_osi quirk should be better added statically, then.

No, I guess the problem here is that acer_wmi doesn't support this
machine yet. I told the ACER WMI maintainer and sent a DSDT image,
but this message was thoroughly ignored.


  $ dmesg|grep -i acer
  [    0.000000] DMI: Acer TM5735/BA51_MV, BIOS V1.04 09/23/2010
  [   71.850534] acer_wmi: Acer Laptop ACPI-WMI Extras
  [   72.350278] acer_wmi: Unable to detect available WMID devices
  
  Machine: Acer Travelmate 5735Z-452G32Mnss

m.
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Joey Lee - April 30, 2011, 2:37 p.m.
Hi Melchior, 

? ??2011-04-30 ? 13:34 +0200?Melchior FRANZ ???
> Dropping Linus from the CC.
> 
> 
> * Takashi Iwai -- Saturday 30 April 2011:
> * * At Sat, 30 Apr 2011 10:32:04 +0200, Melchior FRANZ wrote:
> > > Yes, backlight adjustment generally works on this notebook, but only
> > > with "acpi_osi=Linux" on the command line.
> > 
> > acpi_osi quirk should be better added statically, then.
> 
> No, I guess the problem here is that acer_wmi doesn't support this
> machine yet. I told the ACER WMI maintainer and sent a DSDT image,
> but this message was thoroughly ignored.
> 
> 
>   $ dmesg|grep -i acer
>   [    0.000000] DMI: Acer TM5735/BA51_MV, BIOS V1.04 09/23/2010
>   [   71.850534] acer_wmi: Acer Laptop ACPI-WMI Extras
>   [   72.350278] acer_wmi: Unable to detect available WMID devices
>   
>   Machine: Acer Travelmate 5735Z-452G32Mnss
> 
> m.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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Could you please attach DSDT on this mail or share your kernel bugzilla
number to us?

I found cann't access BKO now?


Thank's
Joey Lee

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Takashi Iwai - May 2, 2011, 12:08 p.m.
At Sat, 30 Apr 2011 13:34:51 +0200,
Melchior FRANZ wrote:
> 
> Dropping Linus from the CC.
> 
> 
> * Takashi Iwai -- Saturday 30 April 2011:
> * * At Sat, 30 Apr 2011 10:32:04 +0200, Melchior FRANZ wrote:
> > > Yes, backlight adjustment generally works on this notebook, but only
> > > with "acpi_osi=Linux" on the command line.
> > 
> > acpi_osi quirk should be better added statically, then.
> 
> No, I guess the problem here is that acer_wmi doesn't support this
> machine yet. I told the ACER WMI maintainer and sent a DSDT image,
> but this message was thoroughly ignored.
> 
> 
>   $ dmesg|grep -i acer
>   [    0.000000] DMI: Acer TM5735/BA51_MV, BIOS V1.04 09/23/2010
>   [   71.850534] acer_wmi: Acer Laptop ACPI-WMI Extras
>   [   72.350278] acer_wmi: Unable to detect available WMID devices
>   
>   Machine: Acer Travelmate 5735Z-452G32Mnss

Hm, but the backlight control is done via the standard ACPI, no?
If so, the fact that acer_wmi doesn't work sounds irrelevant.

BTW, did you try my previous patch?


Takashi
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Melchior FRANZ - May 2, 2011, 1:12 p.m.
* Takashi Iwai -- Monday 02 May 2011:
* > At Sat, 30 Apr 2011 13:34:51 +0200, Melchior FRANZ wrote:
> > * Takashi Iwai -- Saturday 30 April 2011:
> > > acpi_osi quirk should be better added statically, then.
> > 
> > No, I guess the problem here is that acer_wmi doesn't support this
> > machine yet.

> Hm, but the backlight control is done via the standard ACPI, no?

I have no idea. If I were an expert, I would just have sent a
patch, not a bug report. And I prefer fixes to "quirks".  :-P



> BTW, did you try my previous patch?

Works. I hadn't tested it before, because you seemed to wait
for the opinion of some Intel people, and so did I. But thanks
for that code!

m.
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Joey Lee - May 4, 2011, 7:07 a.m.
Hi Melchior, 

? ??2011-05-02 ? 14:08 +0200?Takashi Iwai ???
> At Sat, 30 Apr 2011 13:34:51 +0200,
> Melchior FRANZ wrote:
> > 
> > Dropping Linus from the CC.
> > 
> > 
> > * Takashi Iwai -- Saturday 30 April 2011:
> > * * At Sat, 30 Apr 2011 10:32:04 +0200, Melchior FRANZ wrote:
> > > > Yes, backlight adjustment generally works on this notebook, but only
> > > > with "acpi_osi=Linux" on the command line.
> > > 
> > > acpi_osi quirk should be better added statically, then.
> > 
> > No, I guess the problem here is that acer_wmi doesn't support this
> > machine yet. I told the ACER WMI maintainer and sent a DSDT image,
> > but this message was thoroughly ignored.
> > 
> > 
> >   $ dmesg|grep -i acer
> >   [    0.000000] DMI: Acer TM5735/BA51_MV, BIOS V1.04 09/23/2010
> >   [   71.850534] acer_wmi: Acer Laptop ACPI-WMI Extras
> >   [   72.350278] acer_wmi: Unable to detect available WMID devices
> >   
> >   Machine: Acer Travelmate 5735Z-452G32Mnss
> 
> Hm, but the backlight control is done via the standard ACPI, no?
> If so, the fact that acer_wmi doesn't work sounds irrelevant.
> 
> BTW, did you try my previous patch?
> 
> 
> Takashi

Yes, please try Takashi's previous patch. 

I am tracing bko#34142, but this issue does not related to your
backlight control, because there have _BCM, _BQC declare in your DSDT,
your machine MUST SUPPORTED by standard acpi backlight interface.

Even the acer-wmi can probed on your machine, it cann't help anything
for your backlight control.


Thank's a lot!
Joey Lee

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Patch

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1c1b27c..c0ab771 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -328,6 +328,7 @@  typedef struct drm_i915_private {
 	struct intel_overlay *overlay;
 
 	/* LVDS info */
+	int backlight_combination_mode; /* 0=unknown, -1=no, 1=yes */
 	int backlight_level;  /* restore backlight to this value */
 	bool backlight_enabled;
 	struct drm_display_mode *panel_fixed_mode;
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index a06ff07..320dd5f 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -115,14 +115,24 @@  done:
 static int is_backlight_combination_mode(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	if (INTEL_INFO(dev)->gen >= 4)
-		return I915_READ(BLC_PWM_CTL2) & BLM_COMBINATION_MODE;
-
-	if (IS_GEN2(dev))
-		return I915_READ(BLC_PWM_CTL) & BLM_LEGACY_MODE;
-
-	return 0;
+	int combo_mode;
+	u8 lbpc;
+
+	if (dev_priv->backlight_combination_mode)
+		return dev_priv->backlight_combination_mode > 0;
+
+	pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc);
+	if (!lbpc)
+		combo_mode = 0;
+	else if (INTEL_INFO(dev)->gen >= 4)
+		combo_mode = I915_READ(BLC_PWM_CTL2) & BLM_COMBINATION_MODE;
+	else if (IS_GEN2(dev))
+		combo_mode = I915_READ(BLC_PWM_CTL) & BLM_LEGACY_MODE;
+	else
+		combo_mode = 0;
+
+	dev_priv->backlight_combination_mode = combo_mode ? -1 : 1;
+	return combo_mode;
 }
 
 static u32 i915_read_blc_pwm_ctl(struct drm_i915_private *dev_priv)