At Wed, 22 Aug 2007 10:48:44 -0500, Timur Tabi wrote:
Takashi Iwai wrote:
The driver should deny a too large size if it's unrealistic. But 1MB is realistic for many systems. So, the number depends on the system.
Are there any popular applications that really want a DMA buffer larger than 64KB?
It's something like an urban legend: the bigger, the better. A big buffer seems preferred for applications that require the robust operation. Such a requirement makes a little bit sense although multi-threading and adjusting the RT-priority would give you far better result.
On a side note, I notice that ALSA has some scatter-gather support. If an application uses S/G, I presume the concept of a DMA buffer size doesn't even apply?
The SG-buffer isn't for applications but for drivers. From the application viewpoint, the buffer looks linear.
Takashi