On 2023-02-21 19:55, Jiaxun Yang wrote:

quoted

2023年2月21日 19:46，Robin Murphy [off-list ref] 写道：

On 2023-02-21 18:15, Jiaxun Yang wrote:

quoted

quoted

2023年2月21日 17:54，Christoph Hellwig [off-list ref] 写道：

Can you explain the motivation here?  Also why riscv patches are at
the end of a mips fіxes series?

Ah sorry for any confusion.
So the main purpose of this patch is to fix MIPS’s broken per-device coherency.
To be more precise, we want to be able to control the default coherency for all devices probed from
devicetree in early boot code.

Including the patch which actually does that would be helpful. As it is, patches 4-7 here just appear to be moving an option around for no practical effect.

Well the affect is default coherency of devicetree probed devices are now following dma_default_coherent
instead of a static Kconfig option. For MIPS platform, dma_default_coherent will be determined by boot code.

"Will be" is the issue I'm getting at. We can't review some future 
promise of a patch, we can only review actual patches. And it's hard to 
meaningfully review preparatory patches for some change without the full 
context of that change.

Thanks,
Robin.