Re: ALSA vs. non coherent DMA

2008-05-08 Thread Takashi Iwai
At Thu, 08 May 2008 07:53:11 +1000, Benjamin Herrenschmidt wrote: > > On Wed, 2008-05-07 at 09:22 -0500, Timur Tabi wrote: > > Takashi Iwai wrote: > > > > > This is a mmap of the data record to be shared in realtime with apps. > > > The app updates its data pointer (appl_ptr) on the mmapped buffe

Re: ALSA vs. non coherent DMA

2008-05-07 Thread Benjamin Herrenschmidt
On Wed, 2008-05-07 at 09:22 -0500, Timur Tabi wrote: > Takashi Iwai wrote: > > > This is a mmap of the data record to be shared in realtime with apps. > > The app updates its data pointer (appl_ptr) on the mmapped buffer > > while the driver updates the data (e.g. DMA position, called hwptr) on >

Re: ALSA vs. non coherent DMA

2008-05-07 Thread Grant Likely
On Wed, May 7, 2008 at 8:22 AM, Timur Tabi <[EMAIL PROTECTED]> wrote: > Takashi Iwai wrote: > > > This is a mmap of the data record to be shared in realtime with apps. > > The app updates its data pointer (appl_ptr) on the mmapped buffer > > while the driver updates the data (e.g. DMA position,

Re: ALSA vs. non coherent DMA

2008-05-07 Thread Timur Tabi
Takashi Iwai wrote: > This is a mmap of the data record to be shared in realtime with apps. > The app updates its data pointer (appl_ptr) on the mmapped buffer > while the driver updates the data (e.g. DMA position, called hwptr) on > the fly on the mmapped record. Due to its real-time nature, it

Re: ALSA vs. non coherent DMA

2008-05-06 Thread Takashi Iwai
Hi Ben, thanks for signaling this long-standing issue again. At Tue, 06 May 2008 10:08:28 +1000, Benjamin Herrenschmidt wrote: > > Hi Takashi ! > > I'm bringing up an old thread as I'm just discovering that the problem > still hasn't been fixed. > > There seem to be a few issues with ALSA curr