On Wed, May 15, 2013 at 05:41:12AM +0300, Xenia Ragiadakou wrote: > Hi Sarah, (again) > > Also I noticed that dma_set_coherent_mask() is not called somewhere, > which according to DMA-API-HOWTO.txt, means the even if the DMA mask > is set to 64 bits by dma_set_mask, dma_alloc_coherent and > dma_pool_alloc wont return 64 bit addresses (32 MSbits wont be > addressed).
Another good question for Alan, and the USB and PCI list. (Alan, Ksenia is one of the applicants for the FOSS Outreach Program for Women that I've been coordinating: http://kernelnewbies.org/OPWIntro) We do allocate memory using DMA pools, and we do want 64-bit context addresses if the xHCI host controller can handle it. The xHCI driver calls dma_set_mask, but not dma_set_coherent_mask(): temp = xhci_readl(xhci, &xhci->cap_regs->hcc_params); if (HCC_64BIT_ADDR(temp)) { xhci_dbg(xhci, "Enabling 64-bit DMA addresses.\n"); dma_set_mask(hcd->self.controller, DMA_BIT_MASK(64)); } else { dma_set_mask(hcd->self.controller, DMA_BIT_MASK(32)); } Alan, should it be calling dma_set_coherent_mask()? I think I may have noticed the context addresses were never 64-bit addresses, but I didn't think to look whether the host supported 64-bit addresses. I just assumed it could only handle 32-bit addresses. > I hope I'm not doing a huge mistake in my reasonance, and you loose > your time with these emails. Nope, I want you to ask questions, so don't worry about that. Sarah Sharp -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
