On 7/8/2013 3:42 AM, Russell King - ARM Linux wrote:
The problem is the way the arm_dma_limit is set up, all dma allocations
are currently broken regardless of if the actual device supports 64-bit
addresses or not.
Please explain this statement.
The statement was a bit shortsighted given recent discussions. My point
was that on LPAE systems right now without ZONE_DMA, the allocation
fails by default (i.e. no call to set_mask) even if the device could
support 64-bit physical memory. Based on this thread though, drivers
should stop assuming the dma_mask will be set up properly and always set
the mask appropriately.
The conclusion also seems to be that if devices on an LPAE system can't
handle > 32-bit addresses and want to limit via mask, ZONE_DMA must be
set up.
Please correct me if I misunderstood anything.
Thanks,
Laura
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
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