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Re: [PATCH v2] r8169: set coherent DMA mask as well as streaming DMA mask

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Ard Biesheuvel <ard.biesheuvel@linaro.org> :
> 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.biesheuvel@linaro.org>

Acked-by: Francois Romieu <romieu@fr.zoreil.com>

Unless someone plans to plug an acenic, a 83820 (pci-e gem board, anyone ?)
on top of a pci <-> pci-e adapter on this kind of motherboard, no other
network driver that uses the pci_... dma api exhibits this mixed 32 / 64 bit
support bug. I haven't checked devices with 32 < mask < 64 nor plain DMA api
converted ones.

-- 
Ueimor

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[PATCH v2] r8169: set coherent DMA mask as well as streaming DMA mask Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2016-10-14 15:50 +0200
  Re: [PATCH v2] r8169: set coherent DMA mask as well as streaming DMA  mask Francois Romieu <romieu@fr.zoreil.com> - 2016-10-14 23:00 +0200
  Re: [PATCH v2] r8169: set coherent DMA mask as well as streaming  DMA mask David Miller <davem@davemloft.net> - 2016-10-15 23:40 +0200

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