On Thu, Aug 09, 2012 at 09:50:57AM +0200, Takashi Iwai wrote: > 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.
Right... the deferred probe would mess up the matching done by the static dev variable. So maybe a proper implementation that uses asynchronous firmware loading is inevitable. Thierry
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