lkml.org 
[lkml]   [2012]   [Aug]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] ALSA: hda - Defer probe when loading patch firmware
At Thu, 09 Aug 2012 09:42:48 +0200,
Takashi Iwai wrote:
>
> At Thu, 9 Aug 2012 09:36:42 +0200,
> Thierry Reding wrote:
> >
> > On Thu, Aug 09, 2012 at 09:31:30AM +0200, Takashi Iwai wrote:
> > > At Thu, 9 Aug 2012 09:08:13 +0200,
> > > Thierry Reding wrote:
> > > >
> > > > On Thu, Aug 09, 2012 at 08:57:13AM +0200, Takashi Iwai wrote:
> > > > > At Thu, 9 Aug 2012 08:45:23 +0200,
> > > > > Thierry Reding wrote:
> > > > > >
> > > > > > Recent changes to the firmware loading helpers cause drivers to stall
> > > > > > when firmware is loaded during the module_init() call. The snd-hda-intel
> > > > > > module requests firmware if the patch= parameter is used to load a patch
> > > > > > file. This patch works around the problem by deferring the probe in such
> > > > > > cases, which will cause the module to load successfully and the driver
> > > > > > binding to the device outside the module_init() call.
> > > > >
> > > > > Is the "recent" change meant 3.6 kernel, or in linux-next?
> > > > >
> > > > > In anyway, I don't understand why such a change was allowed. Most
> > > > > drivers do call request_firmware() at the device probing time.
> > > > > If this really has to be resolved in the driver side, it must be a bug
> > > > > in the firmware loader core code.
> > > >
> > > > A good explanation of the problem and subsequent discussion can be found
> > > > here:
> > > >
> > > > http://article.gmane.org/gmane.linux.drivers.video-input-infrastructure/49975
> > >
> > > Yeah, but it doesn't justify this ugly module option.
> > > It's a simple bug. Papering over it with this option doesn't fix
> > > anything.
> >
> > It's not an option, all it does is defer probing if and only if the
> > patch parameter was specified to make sure the firmware load won't
> > stall. I realize that this may not be an optimal solution, but at least
> > it fixes the problem with no fallout.
>
> Ah sorry, I misread the patch.
>
> Then it shouldn't be checked at that point. Since 3.5 kernel, the
> probing code was already split for vga_switcheroo support. The point
> you added is the second stage.

... and the patch won't work properly if there are multiple HD-audio
controllers. Hmm.


Takashi



\
 
 \ /
  Last update: 2012-08-09 10:24    [from the cache]
©2003-2011 Jasper Spaans