dma_alloc_coherent() memory allocation failure with more than 4mb
I am trying to allocate a 5-page-800x600 frame buffer(roughly 5mb). But during DRAM memory map initialization, dma_alloc_coherent() only returns a zero pointer or does not allocate the buffer. It used to work with just allocating a 4-page frame buffer(4mb).
I have already tried setting CONSISTENT_DMA_SIZE to 8mb, 10mb, and 12mb. But this doesn't seem to have any effect. Is there any other setting I'm over looking?
BTW, my Kernel Version is 2.6.10. I wonder of this version cannot support large memory allocations.