Messages in this thread | | | Date | Fri, 7 Aug 2009 10:12:23 +0200 | From | Matthieu CASTET <> | Subject | Re: How to efficiently handle DMA and cache on ARMv7 ? (was "Is get_user_pages() enough to prevent pages from being swapped out ?") |
| |
Laurent Pinchart a écrit : > On Thursday 06 August 2009 20:46:14 David Xiao wrote: > > Think about the simple following use case. An application wants to display > video it acquires from the device to the screen using Xv. The video buffer is > allocated by Xv. Using the v4l2 user pointer streaming method, the device can > DMA directly to the Xv buffer. Using driver-allocated buffers, a memcpy() is > required between the v4l2 buffer and the Xv buffer. > v4l2 got an API (overlay IRRC) that allow drivers to write directly in framebuffer memory. BTW Xv buffer is not always in video memory and the X driver can do a memcpy.
Matthieu -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |