From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: [PATCH] snd-via82xx: Support all sample rate conversion capabilities of DXS channels Date: Mon, 11 Apr 2005 16:06:06 +0200 Message-ID: References: <20050410155320.GA2101@procyon.home> Mime-Version: 1.0 (generated by SEMI 1.14.5 - "Awara-Onsen") Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: <20050410155320.GA2101@procyon.home> 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: Sergey Vlasov Cc: alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org At Sun, 10 Apr 2005 19:53:20 +0400, Sergey Vlasov wrote: > > Hello! > > The current snd-via82xx driver does not use all capabilities of the > DXS channels present in VIA VT8233/5/7 chips. In particular: > > - The driver only accepts sample rates which are supported by the > AC'97 codec; however, the controller is able to perform sample rate > conversion itself, therefore the codec limits do not apply (and even > non-standard rates can be used). > > - The driver forces sample rates for all 4 DXS subdevices to be the > same; however, the controller has separate sample rate converters > for each channel. > > This patch adds support for these capabilities of the VT823x > controller to the snd-via82xx driver. I have tested it with the ASUS > A8V Deluxe board (VT8237 southbridge, Realtek ALC850 codec), with > simultaneous output with different sample rates (48000, 44100, 8000, > and some non-standard values like 44444, 12345, etc...). The SPDIF > output also seems to work (tested with the Sony MZ-N1 portable > minidisc recorder). > > To avoid breaking support of some other hardware which may not like > this mode, the full DXS support is enabled only for known devices (the > patch adds an entry for ASUS A8V Deluxe), or when the dxs_support=5 > option is used. > > When using dxs_support=5, the AC'97 sample rate is locked at 48000 Hz, > and the controller performs sample rate conversion for each DXS > channel. Therefore output with any sample rate between 8000 and 48000 > Hz is possible even if the codec supports only 48000 Hz (like ALC850, > which does not support VRA). SPDIF rate is also locked to 48000 Hz. > > The patch was made for ALSA CVS version from yesterday. > > Best regards, > Sergey Vlasov > > > ======================================================================= > > Add support for full sample rate conversion capabilities of DXS > channels present in VIA VT8233/5/7 controllers: > > - any sample rate in the 8000 ... 48000 Hz range is supported even if > the AC'97 codec supports only 48000 Hz output; > > - different DXS channels can use different sample rates at the same > time (the controller performs required sample rate conversion and > mixing in hardware). > > Signed-off-by: Sergey Vlasov Thanks. I applied it to CVS. If I understand correctly, this feature should be available on all machines with dxs_support=4, but you added a new dxs_support entry just to be sure not to break, right? BTW, the SPDIF rate should be also 48k in dxs_support=4, too. I'll fix this now... Takashi ------------------------------------------------------- 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