max PWM is zero

max PWM is zero

[Marcos Paulo de Souza]

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Hi lkml,

I'm using the kernel 3.2-rc1 and I'm getting the following message in my 
dmesg:
fixme: max PWM is zero.

I don't remember if this message was here before...

I'm trying to verify what is causing this. I found this waring message in 
the drivers/gpu/drm/i915/intel_panel.c.

There is a comment above  this message, talking about put a code to query 
mode clock or hw clock to set the max PWM.

Bellow is my lspci.

I will be happy if you continue to cc me, and if you need any test, I'm 
able to do this.

00:00.0 Host bridge: Intel Corporation Mobile 4 Series Chipset Memory Controller Hub (rev 09)
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, fast devsel, latency 0
 	Capabilities: [e0] Vendor Specific Information: Len=0a <?>
 	Kernel driver in use: agpgart-intel
 	Kernel modules: intel-agp

00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 09) (prog-if 00 [VGA controller])
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, fast devsel, latency 0, IRQ 44
 	Memory at f8000000 (64-bit, non-prefetchable) [size=4M]
 	Memory at d0000000 (64-bit, prefetchable) [size=256M]
 	I/O ports at 1800 [size=8]
 	Expansion ROM at <unassigned> [disabled]
 	Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
 	Capabilities: [d0] Power Management version 3
 	Kernel driver in use: i915
 	Kernel modules: i915

00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 09)
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, fast devsel, latency 0
 	Memory at f8400000 (64-bit, non-prefetchable) [size=1M]
 	Capabilities: [d0] Power Management version 3

00:1a.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 (rev 03) (prog-if 00 [UHCI])
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, medium devsel, latency 0, IRQ 16
 	I/O ports at 1820 [size=32]
 	Capabilities: [50] PCI Advanced Features
 	Kernel driver in use: uhci_hcd

00:1a.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #5 (rev 03) (prog-if 00 [UHCI])
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, medium devsel, latency 0, IRQ 21
 	I/O ports at 1840 [size=32]
 	Capabilities: [50] PCI Advanced Features
 	Kernel driver in use: uhci_hcd

00:1a.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #6 (rev 03) (prog-if 00 [UHCI])
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, medium devsel, latency 0, IRQ 19
 	I/O ports at 1860 [size=32]
 	Capabilities: [50] PCI Advanced Features
 	Kernel driver in use: uhci_hcd

00:1a.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #2 (rev 03) (prog-if 20 [EHCI])
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, medium devsel, latency 0, IRQ 19
 	Memory at f8704000 (32-bit, non-prefetchable) [size=1K]
 	Capabilities: [50] Power Management version 2
 	Capabilities: [58] Debug port: BAR=1 offset=00a0
 	Capabilities: [98] PCI Advanced Features
 	Kernel driver in use: ehci_hcd

00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03)
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, fast devsel, latency 0, IRQ 43
 	Memory at f8700000 (64-bit, non-prefetchable) [size=16K]
 	Capabilities: [50] Power Management version 2
 	Capabilities: [60] MSI: Enable+ Count=1/1 Maskable- 64bit+
 	Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00
 	Capabilities: [100] Virtual Channel
 	Capabilities: [130] Root Complex Link
 	Kernel driver in use: snd_hda_intel
 	Kernel modules: snd-hda-intel

00:1c.0 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 1 (rev 03) (prog-if 00 [Normal decode])
 	Flags: bus master, fast devsel, latency 0
 	Bus: primary=00, secondary=02, subordinate=03, sec-latency=0
 	I/O behind bridge: 00002000-00002fff
 	Memory behind bridge: f4000000-f5ffffff
 	Prefetchable memory behind bridge: 00000000f0000000-00000000f1ffffff
 	Capabilities: [40] Express Root Port (Slot+), MSI 00
 	Capabilities: [80] MSI: Enable+ Count=1/1 Maskable- 64bit-
 	Capabilities: [90] Subsystem: Gammagraphx, Inc. (or missing ID) Device 0000
 	Capabilities: [a0] Power Management version 2
 	Capabilities: [100] Virtual Channel
 	Capabilities: [180] Root Complex Link
 	Kernel driver in use: pcieport
 	Kernel modules: shpchp

00:1c.5 PCI bridge: Intel Corporation 82801I (ICH9 Family) PCI Express Port 6 (rev 03) (prog-if 00 [Normal decode])
 	Flags: bus master, fast devsel, latency 0
 	Bus: primary=00, secondary=04, subordinate=05, sec-latency=0
 	I/O behind bridge: 00003000-00003fff
 	Memory behind bridge: f6000000-f7ffffff
 	Prefetchable memory behind bridge: 00000000f2000000-00000000f3ffffff
 	Capabilities: [40] Express Root Port (Slot+), MSI 00
 	Capabilities: [80] MSI: Enable+ Count=1/1 Maskable- 64bit-
 	Capabilities: [90] Subsystem: Gammagraphx, Inc. (or missing ID) Device 0000
 	Capabilities: [a0] Power Management version 2
 	Capabilities: [100] Virtual Channel
 	Capabilities: [180] Root Complex Link
 	Kernel driver in use: pcieport
 	Kernel modules: shpchp

00:1d.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #1 (rev 03) (prog-if 00 [UHCI])
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, medium devsel, latency 0, IRQ 23
 	I/O ports at 1880 [size=32]
 	Capabilities: [50] PCI Advanced Features
 	Kernel driver in use: uhci_hcd

00:1d.1 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #2 (rev 03) (prog-if 00 [UHCI])
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, medium devsel, latency 0, IRQ 19
 	I/O ports at 18a0 [size=32]
 	Capabilities: [50] PCI Advanced Features
 	Kernel driver in use: uhci_hcd

00:1d.2 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #3 (rev 03) (prog-if 00 [UHCI])
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, medium devsel, latency 0, IRQ 18
 	I/O ports at 18c0 [size=32]
 	Capabilities: [50] PCI Advanced Features
 	Kernel driver in use: uhci_hcd

00:1d.7 USB Controller: Intel Corporation 82801I (ICH9 Family) USB2 EHCI Controller #1 (rev 03) (prog-if 20 [EHCI])
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, medium devsel, latency 0, IRQ 23
 	Memory at f8704400 (32-bit, non-prefetchable) [size=1K]
 	Capabilities: [50] Power Management version 2
 	Capabilities: [58] Debug port: BAR=1 offset=00a0
 	Capabilities: [98] PCI Advanced Features
 	Kernel driver in use: ehci_hcd

00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 93) (prog-if 01 [Subtractive decode])
 	Flags: bus master, fast devsel, latency 0
 	Bus: primary=00, secondary=06, subordinate=06, sec-latency=0
 	Capabilities: [50] Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009

00:1f.0 ISA bridge: Intel Corporation ICH9M LPC Interface Controller (rev 03)
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, medium devsel, latency 0
 	Capabilities: [e0] Vendor Specific Information: Len=0c <?>
 	Kernel modules: iTCO_wdt

00:1f.2 IDE interface: Intel Corporation ICH9M/M-E 2 port SATA IDE Controller (rev 03) (prog-if 8f [Master SecP SecO PriP PriO])
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, 66MHz, medium devsel, latency 0, IRQ 19
 	I/O ports at 18f8 [size=8]
 	I/O ports at 180c [size=4]
 	I/O ports at 18f0 [size=8]
 	I/O ports at 1808 [size=4]
 	I/O ports at 18e0 [size=16]
 	I/O ports at 1810 [size=16]
 	Capabilities: [70] Power Management version 3
 	Capabilities: [b0] PCI Advanced Features
 	Kernel driver in use: ata_piix

00:1f.3 SMBus: Intel Corporation 82801I (ICH9 Family) SMBus Controller (rev 03)
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: medium devsel, IRQ 19
 	Memory at c0000000 (64-bit, non-prefetchable) [size=256]
 	I/O ports at 1c00 [size=32]
 	Kernel driver in use: i801_smbus
 	Kernel modules: i2c-i801

00:1f.5 IDE interface: Intel Corporation ICH9M/M-E 2 port SATA IDE Controller (rev 03) (prog-if 85 [Master SecO PriO])
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, 66MHz, medium devsel, latency 0, IRQ 19
 	I/O ports at 1c50 [size=8]
 	I/O ports at 1c44 [size=4]
 	I/O ports at 1c48 [size=8]
 	I/O ports at 1c40 [size=4]
 	I/O ports at 1c30 [size=16]
 	I/O ports at 1c20 [size=16]
 	Capabilities: [70] Power Management version 3
 	Capabilities: [b0] PCI Advanced Features
 	Kernel driver in use: ata_piix

04:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 02)
 	Subsystem: FIRST INTERNATIONAL Computer Inc Device 3009
 	Flags: bus master, fast devsel, latency 0, IRQ 42
 	I/O ports at 3000 [size=256]
 	Memory at f6000000 (64-bit, non-prefetchable) [size=4K]
 	Memory at f2000000 (64-bit, prefetchable) [size=64K]
 	[virtual] Expansion ROM at f2020000 [disabled] [size=128K]
 	Capabilities: [40] Power Management version 3
 	Capabilities: [50] MSI: Enable+ Count=1/1 Maskable- 64bit+
 	Capabilities: [70] Express Endpoint, MSI 01
 	Capabilities: [b0] MSI-X: Enable- Count=2 Masked-
 	Capabilities: [d0] Vital Product Data
 	Capabilities: [100] Advanced Error Reporting
 	Capabilities: [140] Virtual Channel
 	Capabilities: [160] Device Serial Number 71-00-00-00-68-4c-e0-00
 	Kernel driver in use: r8169
 	Kernel modules: r8169


* Uma vida sem desafios é uma vida sem razão *
* A life without challanges is a non reason life *

Re: max PWM is zero

[Keith Packard]

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On Sat, 19 Nov 2011 11:26:07 +0000 (Local time zone must be set--see zic manual page), Marcos Paulo de Souza <marcos.mage@gmail.com> wrote:
> So, anybody gets the same message?
> 
> I'm trying the 3.2-rc2 and it gives the same message.
> 
> Again, if you need someone to make tests, or test some patches, I'm 
> able to do this.

Is your machine even using the intel backlight device? You can test this
by:

# cd /sys/class/backlight/intel_backlight

Then look at 'max_brightness' and try echoing a range of numbers from 0
to max_brightness into the brightness file and see if it changes the
backlight.

It's more than possible that your machine is simply using some other
hardware to drive the backlight and that the integrated backlight
controller is simply disabled.

-- 
keith.packard@intel.com

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Re: max PWM is zero

[Keith Packard]

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On Mon, 21 Nov 2011 22:48:21 +0000 (Local time zone must be set--see zic manual page), Marcos Paulo de Souza <marcos.mage@gmail.com> wrote:

> My max_brightness is 1, and my brightness is 0.

Right, we've prevented the internal backlight driver from exposing a max
value of 0 as that's just confusing.

> But, my acpi_video0 have a 
> max_brightness value = 9...

Right, sounds like your device is just using some other backlight
controller, which is perfectly reasonable.

> So, what can I do to silence this warning...? Change the driver of 
> backlight?

If your backlight keys work correctly, then things are fine and perhaps
we should just remove the warning from the driver, or disable the
internal driver when we discover this situation.

This is the first time I've heard of this warning appearing...

-- 
keith.packard@intel.com

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Re: max PWM is zero

[Lucas De Marchi]

On Mon, Nov 21, 2011 at 23:40, Keith Packard <keithp@keithp.com> wrote:
> On Mon, 21 Nov 2011 22:48:21 +0000 (Local time zone must be set--see zic manual page), Marcos Paulo de Souza <marcos.mage@gmail.com> wrote:
>
>> My max_brightness is 1, and my brightness is 0.
>
> Right, we've prevented the internal backlight driver from exposing a max
> value of 0 as that's just confusing.
>
>> But, my acpi_video0 have a
>> max_brightness value = 9...
>
> Right, sounds like your device is just using some other backlight
> controller, which is perfectly reasonable.
>
>> So, what can I do to silence this warning...? Change the driver of
>> backlight?
>
> If your backlight keys work correctly, then things are fine and perhaps
> we should just remove the warning from the driver, or disable the
> internal driver when we discover this situation.
>
> This is the first time I've heard of this warning appearing...

It appears here as well. I think it was since 2.6.39 or 3.0, I'm not sure.

Same card:

00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series
Chipset Integrated Graphics Controller (rev 07) (prog-if 00 [VGA
controller])
	Subsystem: Dell Device 02bb
	Flags: bus master, fast devsel, latency 0, IRQ 45
	Memory at f6400000 (64-bit, non-prefetchable) [size=4M]
	Memory at d0000000 (64-bit, prefetchable) [size=256M]
	I/O ports at 1800 [size=8]
	Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
	Capabilities: [d0] Power Management version 3
	Kernel driver in use: i915

00:02.1 Display controller: Intel Corporation Mobile 4 Series Chipset
Integrated Graphics Controller (rev 07)
	Subsystem: Dell Device 02bb
	Flags: bus master, fast devsel, latency 0
	Memory at f6100000 (64-bit, non-prefetchable) [size=1M]
	Capabilities: [d0] Power Management version 3

My kernel log has:

[drm] Driver supports precise vblank timestamp query.
composite sync not supported
fixme: max PWM is zero.
composite sync not supported


Is this "composite sync not supported" related to this issue?


Lucas De Marchi