Re: [PATCH V2 0/4] PCI: ACPI: Setting up DMA coherency for PCI device from _CCA attribute

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Arnd,

On 8/26/15 01:48, Arnd Bergmann wrote:
On Wednesday 26 August 2015 00:33:25 Suravee Suthikulpanit wrote:
This patch adds support to setup DMA coherency for PCI device using
the ACPI _CCA attribute. According to the ACPI spec, the _CCA attribute
is required for ARM64. Therefore, this patch is a pre-req for ACPI PCI
support for ARM64 which is currently in development.

Also, this should not affect other architectures that does not define
CONFIG_ACPI_CCA_REQUIRED, since the default value is coherent.


We only support ACPI on SBSA compliant platforms, and SBSA mandates
cache-coherent PCI, so I don't think this is actually needed,
just use coherent all the time and do WARN_ON(!CCA) to catch people
that try to incorrectly use ACPI on a non-SBSA platform.

	Arnd

Thanks for pointing out. The CONFIG_ACPI_CCA_REQUIRED is already existed and selected in arch/arm64/Kconfig, and used for both PCI and non-PCI devices. I am not adding anything specific for the PCI case.

Although, I think WARN_ON(!CCA) when it is required is a good idea. I'll find a proper place for it.

Thanks,
Suravee.

--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux IBM ACPI]     [Linux Power Management]     [Linux Kernel]     [Linux Laptop]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Device Mapper]     [Linux Resources]

  Powered by Linux