At Tue, 10 Nov 2009 14:15:27 -0700, Troy Kisky wrote: > > Takashi Iwai wrote: > > At Mon, 09 Nov 2009 12:36:31 -0700, > > Troy Kisky wrote: > >> Takashi Iwai wrote: > >>> Thanks for a quick test! I'll merge it soon. > >>> > >>>> Thanks for spending your time on something you'd rather not. > >>> Well, I'm willing to fix any bugs, of course ;) So I really > >>> appreciated your report and patch. > >>> > >>> But, more important bug still remains -- why single_cmd mode is > >>> activated. Let's track it down. > >>> > >> I have a little more information on that. The RIRB engine is fine > >> but the CORB engine is stopping at seemingly random times. Usually > >> CORB has about 7 commands queued when it switches to single_cmd mode. > >> After the engine dies, even a rmmod/insmod sequence won't revive it. > >> It seems to require a power down/up. I have noticed a couple of things > >> that I thought might be related, but testing didn't show much difference. > >> > >> 1. The Poulsbo manual says that CORB READ Pointer Reset must be cleared > >> back to 0 and read back as 0 to verify that the clear completed correctly. > > > > At which timing? > > The manual was talking about the CORB read pointer reset sequence. It says > to set the bit, verify set, clear the bit, verify clear. Whereas the > normal hda spec says to just set it and forget it, which is what the code does. Hm, CORB read pointer might play actually something for your device, then. > >> 2. azx_corb_send_cmd doesn't compare CORBWP with CORBRP to see if adding > >> an entry will result in an empty queue. > > > > It's because azx_corb_send_cmd is asynchronous. It doesn't wait. > > That's the purpose of CORB being a ring buffer... > > Still, the circular buffer is a fixed size (256 entries in this case). > The code does not detect if you try to stuff 257 entries into the queue. > Actually, 255 entries is the max you should stuff. The next entry being > stuffed will make the read pointer equal the write pointer and the queue > will be empty. I'm not saying this is likely to ever happen. But if it did > happen, you would end up in single_cmd mode. Yes, in theory. But this doesn't happen actually because you usually read the response often. The read sequence synchronizes. thanks, Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
