[alsa-devel] module dependency between i915 and snd-hda-intel

[Wang, Xingchao]

> -----Original Message-----
> From: alsa-devel-bounces at alsa-project.org
> [mailto:alsa-devel-bounces at alsa-project.org] On Behalf Of Takashi Iwai
> Sent: Friday, May 17, 2013 6:45 PM
> To: Wang, Xingchao
> Cc: Li, Jocelyn; Lin, Mengdong; alsa-devel at alsa-project.org; Girdwood, Liam R;
> david.henningsson at canonical.com
> Subject: Re: [alsa-devel] module dependency between i915 and snd-hda-intel
> 
> At Fri, 17 May 2013 10:14:19 +0000,
> Wang, Xingchao wrote:
> >
> >
> > > -----Original Message-----
> > > From: Takashi Iwai [mailto:tiwai at suse.de]
> > > Sent: Friday, May 17, 2013 6:03 PM
> > > To: Wang, Xingchao
> > > Cc: Lin, Mengdong; david.henningsson at canonical.com; Li, Jocelyn;
> > > Girdwood, Liam R; alsa-devel at alsa-project.org
> > > Subject: Re: module dependency between i915 and snd-hda-intel
> > >
> > > At Fri, 17 May 2013 09:55:13 +0000,
> > > Wang, Xingchao wrote:
> > > >
> > > > Hi Takashi,
> > > >
> > > > Seems kernel building will determine the module loading sequence,
> > > > this would
> > > fix the dependency for i915 and snd-hda-intel.
> > > > If we call the i915 module API directly in snd-hda-intel side,
> > > > kernel building will
> > > change the module.dep accordingly like:
> > > > "
> > > > kernel/sound/pci/hda/snd-hda-intel.ko:
> > > > kernel/drivers/gpu/drm/i915/i915.ko
> > > kernel/drivers/gpu/dr     m/drm_kms_helper.ko
> > > kernel/drivers/gpu/drm/drm.ko
> > > kernel/drivers/i2c/algos/i2c-algo-bit.ko kerne l/drivers/acpi/video.ko
> kernel/sound/pci/hda/snd-hda-codec.ko
> > > kernel/sound/core/snd-hwdep.ko ker     nel/sound/core/snd-pcm.ko
> > > kernel/sound/core/snd-timer.ko kernel/sound/core/snd.ko
> > > kernel/sound/s oundcore.ko kernel/sound/core/snd-page-alloc.ko
> > > > "
> > > > So snd-hda-intel will wait for i915 loading. Even I added i915
> > > > into blacklist.conf,
> > > it will force load i915.ko.
> > > >
> > > > So I think the only bad case is no i915 module built-in, that
> > > > would cause
> > > haswell hda initialize fail, and the patch would output error message.
> > >
> > > Is it the result with your patch?  If so, something must be wrong.
> > >
> >
> > No. i'm testing the case to call the API directly.
> > The issue is with current patch to load i915.ko by request_module(),
> > It would take ~50s and symbol_get() would fail, but I can see i915 module
> already there by "lsmod".
> 
> Which distro are you using? 

I'm using ubuntu 12.10, kernel image was built based on daniel's drm-intel-next branch, with latest commits.

Thanks
--xingchao

 I guess you are bitten by a known problem, and
> maybe it's the reason request_module_notime() is used in drm driver.  This
> should have been fixed some time ago in udev, I thought.
> 
> > So is there any difference between request_module() and auto-loading i915
> module?
> 
> Yes.
> 
> 
> Takashi
> 
> > > We don't want to call i915 functions directly from snd-hda-intel.
> > > That's the exact reason symbol_get() is used.  Otherwise i915 module
> > > is always referred, thus always load when HD-audio is used, no
> > > matter which hardware is.
> >
> > Okay, I see.
> >
> > Thanks
> > --xingchao
> > >
> > >
> > > Takashi
> >
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