Re: [alsa-devel] Basic DMA question
Rene,
I have already read the ALSA driver document. What I really like to understand is when DMA transfers are invoked, and what the source and destination for the transfer is.
Regards, Sven
2007/3/26, Rene Herman rene.herman@gmail.com:
On 03/26/2007 03:13 AM, Sven Johnsson wrote:
I'm new to writing ALSA drivers, and I could use some help on clarifying how DMA is used in ALSA.
"Writing an ALSA Driver" is a useful document. Google will find it...
By the way, the alsa-devel mailinglist recently moved from sourceforge.net to alsa-project.org directly and the new list is moderated for non-subscribers. I just approved your message from the moderation queue manually, but please consider subscribing, at:
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
Thanks, Rene
Regards, Sven _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
At Mon, 26 Mar 2007 11:28:59 +0200, Sven Johnsson wrote:
Rene,
I have already read the ALSA driver document. What I really like to understand is when DMA transfers are invoked, and what the source and destination for the transfer is.
The DMA transfer is started/stopped in trigger callback. In the case of typical playback, the source is the buffer the driver allocated (in hw_params callback) and the destination is the hardware. The DMA setup is usually done in prepare callback.
Takashi
Regards, Sven
2007/3/26, Rene Herman rene.herman@gmail.com:
On 03/26/2007 03:13 AM, Sven Johnsson wrote:
I'm new to writing ALSA drivers, and I could use some help on clarifying how DMA is used in ALSA.
"Writing an ALSA Driver" is a useful document. Google will find it...
By the way, the alsa-devel mailinglist recently moved from sourceforge.net to alsa-project.org directly and the new list is moderated for non-subscribers. I just approved your message from the moderation queue manually, but please consider subscribing, at:
http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
Thanks, Rene
Regards, Sven _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
Alsa-devel mailing list Alsa-devel@alsa-project.org http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
On 03/28/2007 12:16 PM, Takashi Iwai wrote:
At Mon, 26 Mar 2007 11:28:59 +0200, Sven Johnsson wrote:
Rene,
I have already read the ALSA driver document. What I really like to understand is when DMA transfers are invoked, and what the source and destination for the transfer is.
The DMA transfer is started/stopped in trigger callback. In the case of typical playback, the source is the buffer the driver allocated (in hw_params callback) and the destination is the hardware. The DMA setup is usually done in prepare callback.
Oh, sorry... had to look at this one before answering but then forgot about it while looking at a local capture problem.
Rene.
participants (3)
-
Rene Herman -
Sven Johnsson -
Takashi Iwai