2.6.28-rc1: [drm:i915] *ERROR* ... Disabling tiling

2.6.28-rc1: [drm:i915] *ERROR* ... Disabling tiling

[Alan Jenkins]

What does this mean, should I do anything about it?  Is tiling nice to have?

It sounds like GEM broke something - though maybe it just added a more 
verbose error report.

System: EeePC 701
Kernel: v2.6.36-rc1-5-g23cf24c
Chipset: Intel mobile 915G-something
Regretably necessary kernel boot option: noapic


[    1.438441] Linux agpgart interface v0.103
[    1.438441] agpgart-intel 0000:00:00.0: Intel 915GM Chipset
[    1.438441] agpgart-intel 0000:00:00.0: detected 7932K stolen memory
[    1.443353] agpgart-intel 0000:00:00.0: AGP aperture is 256M @ 0xd0000000
[    1.443353] [drm] Initialized drm 1.1.0 20060810
[    1.443353] pci 0000:00:02.0: PCI INT A -> Link[LNKA] -> GSI 5 
(level, low) -> IRQ 5
[    1.443353] pci 0000:00:02.0: setting latency timer to 64
[    1.443353] [drm:i915_gem_detect_bit_6_swizzle] *ERROR* Couldn't read 
from MCHBAR.  Disabling
tiling.
[    1.443353] [drm:i915_driver_load] *ERROR* failed to enable MSI


I expect noapic explains the MSI failure.  I can boot without noapic if 
necessary for testing, but I can't run with it because I get nasty hangs 
& reboots.  I don't see why that merits an *ERROR*... anyway, what I'm 
interested in is the "Disabling tiling".

Thanks
Alan

Re: 2.6.28-rc1: [drm:i915] *ERROR* ... Disabling tiling

[Alan Jenkins]

Alan Jenkins wrote:
> What does this mean, should I do anything about it?  Is tiling nice to have?
>
> It sounds like GEM broke something - though maybe it just added a more 
> verbose error report.
>
> System: EeePC 701
> Kernel: v2.6.36-rc1-5-g23cf24c
> Chipset: Intel mobile 915G-something
> Regretably necessary kernel boot option: noapic
>
>
> [    1.438441] Linux agpgart interface v0.103
> [    1.438441] agpgart-intel 0000:00:00.0: Intel 915GM Chipset
> [    1.438441] agpgart-intel 0000:00:00.0: detected 7932K stolen memory
> [    1.443353] agpgart-intel 0000:00:00.0: AGP aperture is 256M @ 0xd0000000
> [    1.443353] [drm] Initialized drm 1.1.0 20060810
> [    1.443353] pci 0000:00:02.0: PCI INT A -> Link[LNKA] -> GSI 5 
> (level, low) -> IRQ 5
> [    1.443353] pci 0000:00:02.0: setting latency timer to 64
> [    1.443353] [drm:i915_gem_detect_bit_6_swizzle] *ERROR* Couldn't read 
> from MCHBAR.  Disabling
> tiling.
> [    1.443353] [drm:i915_driver_load] *ERROR* failed to enable MSI
>
>
> I expect noapic explains the MSI failure.  I can boot without noapic if 
> necessary for testing, but I can't run with it because I get nasty hangs 
> & reboots.  I don't see why that merits an *ERROR*... anyway, what I'm 
> interested in is the "Disabling tiling".
>   

Actually... MSI does seem to be working for my ethernet.

$ grep eth /proc/interrupts
 44:       2446   PCI-MSI-edge      eth1

DRM wasn't using MSI in 2.6.27 though.  So I'm still doubtful that the 
MSI issue is really an "*ERROR*".

Thanks
Alan

Re: 2.6.28-rc1: [drm:i915] *ERROR* ... Disabling tiling

[Alan Jenkins]

Alan Jenkins wrote:
> Alan Jenkins wrote:
>> What does this mean, should I do anything about it?  Is tiling nice 
>> to have?
>>
>> It sounds like GEM broke something - though maybe it just added a 
>> more verbose error report.
>>
>> System: EeePC 701
>> Kernel: v2.6.36-rc1-5-g23cf24c
>> Chipset: Intel mobile 915G-something
>> Regretably necessary kernel boot option: noapic
>>
>>
>> [    1.438441] Linux agpgart interface v0.103
>> [    1.438441] agpgart-intel 0000:00:00.0: Intel 915GM Chipset
>> [    1.438441] agpgart-intel 0000:00:00.0: detected 7932K stolen memory
>> [    1.443353] agpgart-intel 0000:00:00.0: AGP aperture is 256M @ 
>> 0xd0000000
>> [    1.443353] [drm] Initialized drm 1.1.0 20060810
>> [    1.443353] pci 0000:00:02.0: PCI INT A -> Link[LNKA] -> GSI 5 
>> (level, low) -> IRQ 5
>> [    1.443353] pci 0000:00:02.0: setting latency timer to 64
>> [    1.443353] [drm:i915_gem_detect_bit_6_swizzle] *ERROR* Couldn't 
>> read from MCHBAR.  Disabling
>> tiling.

There's no obvious difference in Xorg.log (compared to 2.6.27).  In fact 
it claims to have successfuly enabled tiling.

(**) intel(0): Tiling enabled
(II) intel(0): Attempting memory allocation with tiled buffers.
(II) intel(0): Success.

So these new kernel error messages seem a bit random.

Thanks
Alan

Re: 2.6.28-rc1: [drm:i915] *ERROR* ... Disabling tiling

[Eric Anholt]

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On Mon, 2008-10-27 at 14:27 +0000, Alan Jenkins wrote:
> What does this mean, should I do anything about it?  Is tiling nice to have?
> 
> It sounds like GEM broke something - though maybe it just added a more 
> verbose error report.
> 
> System: EeePC 701
> Kernel: v2.6.36-rc1-5-g23cf24c
> Chipset: Intel mobile 915G-something
> Regretably necessary kernel boot option: noapic
> 
> 
> [    1.438441] Linux agpgart interface v0.103
> [    1.438441] agpgart-intel 0000:00:00.0: Intel 915GM Chipset
> [    1.438441] agpgart-intel 0000:00:00.0: detected 7932K stolen memory
> [    1.443353] agpgart-intel 0000:00:00.0: AGP aperture is 256M @ 0xd0000000
> [    1.443353] [drm] Initialized drm 1.1.0 20060810
> [    1.443353] pci 0000:00:02.0: PCI INT A -> Link[LNKA] -> GSI 5 
> (level, low) -> IRQ 5
> [    1.443353] pci 0000:00:02.0: setting latency timer to 64
> [    1.443353] [drm:i915_gem_detect_bit_6_swizzle] *ERROR* Couldn't read 
> from MCHBAR.  Disabling
> tiling.

This means that something went wrong with our detection of the
CPU-versus-GPU tiling swizzling mode, and object tiling under GEM will
be disabled as a result.  I should get access to an eee 7xx on Thursday
to see what's up with it -- it's supposed to be just a normal 915gm as
far as I know.

> [    1.443353] [drm:i915_driver_load]o  *ERROR* failed to enable MSI

Looks like we emit the error message even if your chipset doesn't
support MSI.  That's a mistake, I'll get it cleaned up.

(MSI didn't actually get supported for integrated graphics until the
G965 for the desktop and GM45 for mobile, though it got supported for
ethernet and PEG earlier than that)

-- 
Eric Anholt
eric@anholt.net                         eric.anholt@intel.com



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Re: 2.6.28-rc1: [drm:i915] *ERROR* ... Disabling tiling

[Alan Jenkins]

On 10/27/08, Eric Anholt <eric-WhKQ6XTQaPysTnJN9+BGXg@public.gmane.org> wrote:
> On Mon, 2008-10-27 at 14:27 +0000, Alan Jenkins wrote:
>> What does this mean, should I do anything about it?  Is tiling nice to
>> have?
>>
>> It sounds like GEM broke something - though maybe it just added a more
>> verbose error report.
>>
>> System: EeePC 701
>> Kernel: v2.6.28-rc1-5-g23cf24c
>> Chipset: Intel mobile 915G-something
>> Regretably necessary kernel boot option: noapic
>>
>>
>> [    1.438441] Linux agpgart interface v0.103
>> [    1.438441] agpgart-intel 0000:00:00.0: Intel 915GM Chipset
>> [    1.438441] agpgart-intel 0000:00:00.0: detected 7932K stolen memory
>> [    1.443353] agpgart-intel 0000:00:00.0: AGP aperture is 256M @
>> 0xd0000000
>> [    1.443353] [drm] Initialized drm 1.1.0 20060810
>> [    1.443353] pci 0000:00:02.0: PCI INT A -> Link[LNKA] -> GSI 5
>> (level, low) -> IRQ 5
>> [    1.443353] pci 0000:00:02.0: setting latency timer to 64
>> [    1.443353] [drm:i915_gem_detect_bit_6_swizzle] *ERROR* Couldn't read
>> from MCHBAR.  Disabling
>> tiling.
>
> This means that something went wrong with our detection of the
> CPU-versus-GPU tiling swizzling mode, and object tiling under GEM will
> be disabled as a result.  I should get access to an eee 7xx on Thursday
> to see what's up with it -- it's supposed to be just a normal 915gm as
> far as I know.

Any news about this tiling error?

It's already been reported as a bug in Ubuntu Jaunty, in the belief
that it "reduces video performance" [1], and is also mentioned on a
similar bug in Fedora [2].

[1] <https://bugzilla.redhat.com/show_bug.cgi?id=444328#c37>
[2] <https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/329266>

Thanks
Alan

Re: 2.6.28-rc1: [drm:i915] *ERROR* ... Disabling tiling

[Alan Jenkins]

On 3/23/09, Alan Jenkins <sourcejedi.lkml-gM/Ye1E23mwN+BqQ9rBEUg@public.gmane.org> wrote:
> On 10/27/08, Eric Anholt <eric-WhKQ6XTQaPysTnJN9+BGXg@public.gmane.org> wrote:
>> On Mon, 2008-10-27 at 14:27 +0000, Alan Jenkins wrote:
>>> What does this mean, should I do anything about it?  Is tiling nice to
>>> have?
>>>
>>> It sounds like GEM broke something - though maybe it just added a more
>>> verbose error report.
>>>
>>> System: EeePC 701
>>> Kernel: v2.6.28-rc1-5-g23cf24c
>>> Chipset: Intel mobile 915G-something
>>> Regretably necessary kernel boot option: noapic
>>>
>>>
>>> [    1.438441] Linux agpgart interface v0.103
>>> [    1.438441] agpgart-intel 0000:00:00.0: Intel 915GM Chipset
>>> [    1.438441] agpgart-intel 0000:00:00.0: detected 7932K stolen memory
>>> [    1.443353] agpgart-intel 0000:00:00.0: AGP aperture is 256M @
>>> 0xd0000000
>>> [    1.443353] [drm] Initialized drm 1.1.0 20060810
>>> [    1.443353] pci 0000:00:02.0: PCI INT A -> Link[LNKA] -> GSI 5
>>> (level, low) -> IRQ 5
>>> [    1.443353] pci 0000:00:02.0: setting latency timer to 64
>>> [    1.443353] [drm:i915_gem_detect_bit_6_swizzle] *ERROR* Couldn't read
>>> from MCHBAR.  Disabling
>>> tiling.
>>
>> This means that something went wrong with our detection of the
>> CPU-versus-GPU tiling swizzling mode, and object tiling under GEM will
>> be disabled as a result.  I should get access to an eee 7xx on Thursday
>> to see what's up with it -- it's supposed to be just a normal 915gm as
>> far as I know.
>
> Any news about this tiling error?
>
> It's already been reported as a bug in Ubuntu Jaunty, in the belief
> that it "reduces video performance" [1], and is also mentioned on a
> similar bug in Fedora [2].
>
> [1] <https://bugzilla.redhat.com/show_bug.cgi?id=444328#c37>
> [2]
> <https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/329266>

Ah, I should also mention that I still see the error on the latest RC,
2.6.29-rc8.

Alan