Remove bogus default y for DMAR and NET_DMA
PATCH 1/1 Remove bogus default y for DMAR and NET_DMA
Andrew, please queue for next merge. Thanks.
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No reason I can think of of making them default y Most people don't have the hardware and with default y they just pollute lots of configs during make oldconfig.
arch/x86_64/Kconfig +0 -1
@@ -753,7 +753,6 @@ config PCI_DOMAINS config DMAR bool "Support for DMA Remapping Devices (EXPERIMENTAL)" depends on PCI_MSI && ACPI && EXPERIMENTAL - default y help DMA remapping (DMAR) devices support enables independent address translations for Direct Memory Access (DMA) from devices.
drivers/dma/Kconfig +0 -1
@@ -43,7 +43,6 @@ comment "DMA Clients" config NET_DMA bool "Network: TCP receive copy offload" depends on DMA_ENGINE && NET - default y help This enables the use of DMA engines in the network stack to offload receive copy-to-user operations, freeing CPU cycles.
arch/x86_64/Kconfig config PCI_DOMAINS · line 758
Quoted 12 lines · Andi Kleen
Index: linux-2.6.24-rc1-hack/arch/x86_64/Kconfig
===================================================================arch/x86_64/Kconfig +0
-1@@ -753,7 +753,6 @@ config PCI_DOMAINS config DMAR bool "Support for DMA Remapping Devices (EXPERIMENTAL)" depends on PCI_MSI && ACPI && EXPERIMENTAL - default y help DMA remapping (DMAR) devices support enables independent address translations for Direct Memory Access (DMA) from devices.
ACK
drivers/dma/Kconfig comment "DMA Clients" · line 48
Quoted 12 lines
Index: linux-2.6.24-rc1-hack/drivers/dma/Kconfig
===================================================================drivers/dma/Kconfig +0
-1@@ -43,7 +43,6 @@ comment "DMA Clients" config NET_DMA bool "Network: TCP receive copy offload" depends on DMA_ENGINE && NET - default y help This enables the use of DMA engines in the network stack to offload receive copy-to-user operations, freeing CPU cycles.
ACK -- but its arguable that given the current code, its worth setting this if DMA_ENGINE is also set.
Quoted 20 lines
From: Jeff Garzik [mailto:[email protected]]
arch/x86_64/Kconfig config PCI_DOMAINS · line 757
Quoted 11 lines · Andi Kleen
Index: linux-2.6.24-rc1-hack/arch/x86_64/Kconfig
===================================================================arch/x86_64/Kconfig +0
-1@@ -753,7 +753,6 @@ config PCI_DOMAINS config DMAR bool "Support for DMA Remapping Devices (EXPERIMENTAL)" depends on PCI_MSI && ACPI && EXPERIMENTAL - default y help DMA remapping (DMAR) devices support enablesindependent address
arch/x86_64/Kconfig config PCI_DOMAINS · line 758
Quoted 1 line
arch/x86_64/Kconfig +0
-0translations for Direct Memory Access (DMA) from devices.ACK
Quoted 16 lines
drivers/dma/Kconfig comment "DMA Clients" · line 48
Quoted 12 lines
Index: linux-2.6.24-rc1-hack/drivers/dma/Kconfig
===================================================================drivers/dma/Kconfig +0
-1@@ -43,7 +43,6 @@ comment "DMA Clients" config NET_DMA bool "Network: TCP receive copy offload" depends on DMA_ENGINE && NET - default y help This enables the use of DMA engines in the network stack to offload receive copy-to-user operations, freeing CPU cycles.ACK -- but its arguable that given the current code, its worth setting this if
DMA_ENGINEis also set.
The intent is to give us a DMA offload for NIC-to-user operations. At the moment the ioatdma device is the only gizmo supporting this through NET_DMA, and is the only DMA_ENGINE supported on x86. As more devices are made available through DMA_ENGINE on platforms that don't have ioatdma, removing the "default y" makes sense. I agree that this is ACK-able, but under the "it should just work" philosophy, and with the Intel servers coming out with the hardware support, it may want to wait until there are more DMA_ENGINE choices.
In any case, I'll ACK this and let the maintainers decide on the timing.
sln