On Mon, 21.12.09 17:26, Bu, Long (long.bu at intel.com) wrote: > Hi all, > There are some Inel HDA codecs like ALC272 that inverse phase > of one channel when capturing.. remap_channels remaps stereo to > mono by simply add one channel to another. the sum is always very > very close to zero. > > ALSA works around this by using "copy" route policy for all > Intel-HAD card which is equivalent with PA_RESAMPLER_NO_REMAP set in > PA's resampler. > > Attach is a patch that set a REMAP flag for source when its > underlying H/W is ALC 272. Then set REMAP flag for source-outputs > associated with this source. Hmm, I am not convinced this is the right approach. The NO_REMAP flag simply disables any kind of remapping. That includes disabling remapping for surround playback and for example if you have a stereo stream with R and L reversed that this is reorder when you play it back on a device which has L first and R second. I think the effect of this patch is way more than you actually need, right? Also, I am quite confident that the right place to fix this is actually ALSA userspace and not PA. I'd prefer not to see device-specific hacks in PA and also I believe that this problem needs fixing for all ALSA clients, not just PA? Could you bring this up on the ALSA ML? Lennart -- Lennart Poettering Red Hat, Inc. lennart [at] poettering [dot] net http://0pointer.net/lennart/ GnuPG 0x1A015CC4
