On Wednesday 08 May 2013, Rob Herring wrote: > On 05/08/2013 02:11 AM, Matthijs Kooijman wrote: > > https://lkml.org/lkml/2012/12/4/54 > > > > And here's the previous attempt, to which Rob Herring refers in a reply. > > > > https://lists.ozlabs.org/pipermail/devicetree-discuss/2012-March/013180.html > > I believe most of the issues have been around supporting ARM LPAE > systems. There is a much more simple approach to address this by using > the dma_addr_t size to set the coherent_dma_mask which I have queued for > 3.11: > > https://patchwork-mail1.kernel.org/patch/2495861/ Hmm, this approach seems wrong -- a lot of devices I expect cannot actually do DMA to addresses beyond 4GB. A better default would be to use a 32 bit mask for all devices and override the ones that actually matter for performance and are known to be 64-bit DMA capable. Laura, you obviously tried this code on an LPAE-enabled system. Have you had a look in the hardware manual which DMA masters in the system are actually 64-bit capable? Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
