Date: Fri, 13 Feb 2009 09:57:10 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-hackers@freebsd.org Cc: Patrick =?iso-8859-1?q?Lamaizi=E8re?= <patfbsd@davenulle.org> Subject: Re: bus_dmamem_alloc() and BUS_DMA_WAITOK Message-ID: <200902130957.10997.jhb@freebsd.org> In-Reply-To: <20090213152205.0eccafb0@baby-jane.lamaiziere.net> References: <20090213152205.0eccafb0@baby-jane.lamaiziere.net>
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On Friday 13 February 2009 9:22:05 am Patrick Lamaizi=E8re wrote: > Hello, >=20 > I would like to know if it is safe to use the BUS_DMA_WAITOK flag with > bus_dmamem_alloc(), in the context of the device_attach routine? Many > drivers use BUS_DMA_NOWAIT. Yes, it is ok to use in an attach routine. > I need a 32Ko buffer and on low memory my driver cannot attach > (bus_dmamem_alloc returns ENOMEM). Will BUS_DMA_WAITOK help in this > case? I'm not sure if it will really help, though. You might end up blocking=20 forever (or a long time) until a 32k region is freed. =2D-=20 John Baldwin
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