From: Ard Biesheuvel <ard.biesheu...@linaro.org>
Date: Fri, 14 Oct 2016 12:39:30 +0100
> PCI devices that are 64-bit DMA capable should set the coherent
> DMA mask as well as the streaming DMA mask. On some architectures,
> these are managed separately, and so the coherent DMA mask will be
> left at its default value of 32 if it is not set explicitly. This
> results in errors such as
>
> r8169 Gigabit Ethernet driver 2.3LK-NAPI loaded
> hwdev DMA mask = 0x00000000ffffffff, dev_addr = 0x00000080fbfff000
> swiotlb: coherent allocation failed for device 0000:02:00.0 size=4096
> CPU: 0 PID: 1062 Comm: systemd-udevd Not tainted 4.8.0+ #35
> Hardware name: AMD Seattle/Seattle, BIOS 10:53:24 Oct 13 2016
>
> on systems without memory that is 32-bit addressable by PCI devices.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
...
> @@ -8281,6 +8282,8 @@ static int rtl_init_one(struct pci_dev *pdev, const
> struct pci_device_id *ent)
> dev->features |= NETIF_F_HIGHDMA;
> } else {
> rc = pci_set_dma_mask(pdev, DMA_BIT_MASK(32));
> + if (!rc)
> + rc = pci_set_consistent_dma_mask(pdev,
> DMA_BIT_MASK(32));
As you state 32-bit is the default, therefore this part of your patch is
unnecessary.
