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--- resources:tools-software:linux-software:libiio_tips_tricks [20 Aug 2021 10:30] – [Linux Contiguous Memory Allocator (or CMA)] Michael Hennerich
+++ resources:tools-software:linux-software:libiio_tips_tricks [20 Aug 2021 10:49] (current) – [Capturing large contiguous buffers] Michael Hennerich
@@ Line 61: / Line 61: @@
 ===== Capturing large contiguous buffers =====
-Set kernel buffer count to 1
+  - Set kernel buffer count to 1
+  - Increase **IIO buffer DMA max block size** parameter to at least the size of your desired contiguous buffer
+  - Make sure your CMA size is significantly bigger (CMA is used by various other DMA capable devices in your Linux system)
+  - AXI_DMAC controller limits length of the transfers to 2**DMA_LENGTH_WIDTH. The default is 24 so your max transfer size is 16777216 bytes. You may need to increase that and rebuild your design. Please see here: [[:/resources/fpga/docs/axi_dmac#synthesis_configuration_parameters| Synthesis Configuration Parameters]]

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