From mboxrd@z Thu Jan 1 00:00:00 1970 From: Manuel Jander Subject: Re: Re: au8830 - front / rear channels swapped after first play and Surround40 Date: Sat, 12 Mar 2005 22:10:21 -0300 Message-ID: <1110676221.4034.28.camel@localhost> References: <4232B5ED.1080508@netvigator.com> Reply-To: mjander@users.sourceforge.net Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit In-Reply-To: <4232B5ED.1080508@netvigator.com> Sender: alsa-devel-admin@lists.sourceforge.net Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Raymond , alsa-devel , openvortex-dev List-Id: alsa-devel@alsa-project.org Hi Raymond, On Sat, 2005-03-12 at 17:27 +0800, Raymond wrote: > > > 3) Is the bug related to "vortex: IRQ fifo error" ? > > > No, thats not a bug. Thats normal. > > http://lists.gnu.org/archive/html/openvortex-dev/2004-03/msg00007.html > > I think the front/rear swap bug is related to that "vortex: IRQ fifo error". AFAIK the FIFO error occurs only one time, the first time data is being DMA'ed. It could be that this error is some kind of data underrun, and it does only happen once, because we never flush the FIFO's when stopping a stream. Remaining data in the FIFO's may be messing the channel deinterlacer, because the amount of data loaded in the fifo is random, generating a random offset. Since the the PCI bus is 32 bit wide, that problem would not affect stereo streams, because one 32 bit transaction maps to two 16 bit samples. Only where a frame is more that 32bits, this problem would become apparent. This is just a theory, but maybe it could be worth a try, to enforce a absolute flush of the FIFO data when stopping a DMA stream. > As the hardware equalizer is only connected from the front channels to > the CODECOUT(0/1) in the ALSA au88x0 driver when playing at 4 channel > sound through hw:0,0 (adb) > [snip!] > It seem that the patch mentioned in > > http://lists.gnu.org/archive/html/openvortex-dev/2003-12/msg00009.html > > intened to fixed the problem in the OSS application in > > http://lists.gnu.org/archive/html/openvortex-dev/2003-11/msg00016.html I'm not that sure that these things are related directly. The patch in my opinion is just hiding either a hardware issue or a software problem. It may be related to the the way the fifos are stopped and resumed. > > 1) Is the FIFO is still suspending not stopped ? Don't know. AFAIK the fifos can be stopped or just paused. What difference that makes, i don't know. Best Regards -- Manuel Jander Electronic Engineer ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click