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In other words, set URB_FREE_COHEREN= T=20 > to 0x0200 and change URB_DIR_IN to 0x0400. Hi, but what sense does this patch make? You use coherent allocations to avoid repeated DMA synchronizations. That is sort of incompatible with the notion of discarding the buffer automatically. =C2=A0=C2=A0=C2=A0 Regards =C2=A0=C2=A0=C2=A0 =C2=A0=C2=A0=C2=A0 Oliver