r8169: default to 64-bit DMA on recent PCIe chips

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The current logic around the 'use_dac' module parameter prevents the
r81969 driver from being loadable on 64-bit systems without any RAM
below 4 GB when the parameter is left at its default value.

So introduce a new default value -1 which indicates that 64-bit DMA
should be enabled on sufficiently recent PCIe chips, i.e., versions
RTL_GIGA_MAC_VER_18 or later. Explicit param values of 0 or 1 retain
the existing behavior of unconditionally enabling/disabling 64-bit DMA
on 64-bit architectures (i.e., regardless of the type and version of the
chip)

Since PCIe chips do not need to CPlusCmd Dual Address Cycle to be set,
make that conditional on the device type as well.

Cc: Realtek linux nic maintainers <nic_swsd@realtek.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

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This commit is contained in:

Ard Biesheuvel 2016-05-14 22:40:15 +02:00 • committed by David S. Miller

parent 81003bc924

commit 27896c83fe

1 changed files with 25 additions and 19 deletions

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drivers/net/ethernet/realtek/r8169.c

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