From mboxrd@z Thu Jan 1 00:00:00 1970 From: Manu Sharma Subject: alsa issues on h5500 handheld Date: Wed, 01 Dec 2004 17:46:53 +0100 Message-ID: <41ADF57D.5090005@ma.tech.ascom.ch> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: 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: alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org Hi, I am using a iPAQ h5500 runing familiar on it. The alsa drivers for this device are not part of official alsa sources, they are available from handhelds cvs. When I try to record sound () for a certain duration, the recording gets over in half the configured time. For eg "time arecord -d 10 recording" gives the following output ... Recording WAVE 'recording' : Unsigned 8 bit, Rate 8000 Hz, Mono real 0m 5.16s user 0m 0.93s sys 0m 2.78s As far as I could figure out, the reason seems to be related to strange arrangement of things. The codec (ak4535) samples mono only, but the PXA's internal interface between DMA engine and I2S device controller is stereo. For this reason, all DMA configurations in the driver are done considering a stereo interface; additionally the driver configures its 'snd_pcm_hardware_t' structure's channel fields (for capture) as : channels_min = 2 channels_max = 2 My questions are ... (i) Is forcing the device to be stereo (when it is actually mono), the right way to implement as per alsa design OR should the driver be converting DMA samples back to mono, so that things are consistent all along ? (ii) What could be the reason of sample times being half of expected time, specially when the driver is registered as a stereo device ? Thanks in advance Manu ------------------------------------------------------- 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://productguide.itmanagersjournal.com/