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Inputs needed : failure to allocate coherent buffer #93
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No Idea. That seems like a crazy large amount of memory to expect to get out of the CMA. Not sure if it supports that. There may also be bugs in the ancient kernel. Either way this isn't really a switchtec issue... You'll probably need to dig into the CMA code to figure out what is going on. |
Here are some settings we have used which have worked for large allocations.
CONFIG_*CMA*_AREAS=100
CONFIG_*CMA*_SIZE_MBYTES=4096
CONFIG_*CMA*_SIZE_SEL_MBYTES=y
CONFIG_*CMA*_ALIGNMENT=12
Did not change swiotlb boot parameter from default. Also, note that we
were booting in 64-bit mode, which you might need to do for large
allocations also.
Eric
…On Wed, Oct 7, 2020 at 3:33 PM Manish Dusane ***@***.***> wrote:
With 1.2rc3 driver i am trying to allocate 128 M of coherent memory using
dma_alloc_coherent. which fails, even 64M allocation fails - at swiotlb
buffer full.. (32 M works though). I have tried combos of following configs
CMA configs (CONFIG_CMA_SIZE_MBYTES = 256, CONFIG_CMA_ALIGNMENT=12), high
value of swiotlb=65535 in cmdline. tried explicitely setting
dma_coherent_mask. But still i hit the failure. Any suggestion what i am
missing ?
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@epilmore These configs worked for me, Thanks. I am not completely sure of all its side effects though. |
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With 1.2rc3 driver i am trying to allocate 128 M of coherent memory using dma_alloc_coherent. which fails, even 64M allocation fails - at swiotlb buffer full.. (32 M works though). I have tried combos of following configs CMA configs (CONFIG_CMA_SIZE_MBYTES = 256, CONFIG_CMA_ALIGNMENT=12), high value of swiotlb=65535 in cmdline. tried explicitely setting dma_coherent_mask. But still i hit the failure. Any suggestion what i am missing ? This is with 4.4.36
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